RESEARCHES ON THE FLORA OF THE
COAL-BALLS FROMquot; THE quot;FINEFRAU-
.NEBENBANKquot; HORIZON IN THE PRO^
yiNCE OF LIMBURG quot;(THE NETHERLANDS)

RESEARCHES ON THE FLORA OF THE COAL-BALLS
FROM THE quot;FINEFRAU-NEBENBANKquot; HORIZON IN
THE PROVINCE OF LIMBURG (THE NETHERLANDS)

RESEARCHES ON THE FLORA OF THE
COAL-BALLS FROM THE quot;FINEFRAU-
NEBENBANKquot; HORIZON IN THE PRO-
VINCE OF LIMBURG (THE NETHERLANDS)

PROEFSCHRIFT TER VERKRIJGING VAN DEN
GRAAD VAN DOCTOR IN DE WIS- EN NA-
TUURKUNDE AAN DE RIJKSUNIVERSITEIT
TE UTRECHT, OP GEZAG VAN DEN RECTOR-
MAGNIFICUS DR B. J. H. OVINK, HOOGLEERAAR
IN DE FACULTEIT DER LETTEREN EN WIJS-
BEGEERTE, VOLGENS BESLUIT VAN DEN
SENAAT DER UNIVERSITEIT TEGEN DE
BEDENKINGEN VAN DE FACULTEIT DER
WIS- EN NATUURKUNDE TE VERDEDIGEN,
OP DINSDAG 3 JULI 1928, DES NAMIDDAGS

Het is mij een aangename plicht, mijn dank te betuigen aan allen, die, hetzij voor, hetzij gedurende
mijn studie medegewerkt hebben aan mijn wetenschappelijke ontwikkeling en die bij daardoor in staat gesteld
hebben dit onderwerp te bewerken.

Hooggeleerde NiERSTRASZ, Uw bezielde colleges over vergelijkende Anatomie hebben mij geleerd, onze
wetenschappelijke kennis op de juiste waarde te schatten.

. Hooggeleerde TamMES en Zeergeleerde SiRKS, U dank ik mijn kennis van de Erfelijkheidsleer.

Hooggeleerde SCHOUTE, Uw lessen op de H.B.S. hebben mij er toe gebracht, Botanie te gaan studeeren.
Daarnaast dank ik U voor de belangstelling, die Gij in mij getoond hebt gedurende mijn studietijd en voor
hetgeen ik van U mocht leeren in mijn Groningsche jaar.

Hooggeleerde RUTTEN, Uw colleges hebben mij voorbereid om het geologische deel van de literatuur
over mijn onderwerp te begrijpen.

Hooggeleerde PULLE, hooggeachte promotor: als liefhebber-florist kwam ik aan als student, als weten-
schappelijk florist, zij het dan ook „fossielquot;, verlaat ik de Universiteit. Uw hulp en leiding hebben mij steeds
in het goede spoor gehouden.

It was not before the beginning of the year 1926, that coal-balls were found in the Dutch coal-district
and I accepted gladly the offer of Dr. W. j. jongmans to do the preliminary research-work on this beautifui

(KOOPMANS 1927), contammg a short enumeration of the species found at the date of publication

LOCALITY. - The Dutch coal-balls are found in the F i n e f r a u - N e b e n b a n k seam of the
Domaniale Mijn at K e r k r a d e, Dutch Limburg. Usually they are somewhat round in shape, their diameter
varying from 1 to 25 cm. At one place, the whole seam appears to be petrified, a bed of dolomite being found
instead of a seam of coal containing concretions.

STRATIGRAPHY. — Table A shows the horizon in which our coal-balls are found. As Dr. W.
}. JONGMANS has authorized me to announce an article by him on the stratigraphy of this horizon, which will
appear in the quot;Jaarverslag 1927quot; (Annual report) of the „Geologisch Bureau voor het Nederlandsche Mijn-
gebiedquot;, it is unnecessary to go into details of this subject.

FORMATION OF COAL-BALLS. — Coal-balls are calcareous concretions, which are only found
in those seams which have a marine roof, indicative of slow submergence by the sea. They consist of a mass
of plant remains, which has been completely penetrated by inorganic matter, much in the same way as plants
prepared for microtome-cutting are impregnated by paraffine, the salts having been derived from the sea
which deposited the roof. A few roof-nodules have been found also, which, however, unfortunately do not
enclose any plant-remains, containing only Goniatite shells. As to further particulars regarding the origin and
the structure of coal-balls, I refer to the comprehensive article by StoPES AND WATSON (1909).

PRESERVATION. — It is very curious that the organic tissues in the Dutch coal-balls and in those
from the colliery Rheinpreussen, both of which belong to the Finefrau-Nebenbank seam, are pitch-black,
while those from the English material and from the German Katharina seam are of various shades of
brown, the carbonization of the Dutch and German Finefrau-Nebenbank material having gone
further than in the other nodules. In many cases the plant-remains are preserved with great beauty, although
I must own, that the details as seen in English slides are often not present in the Dutch balls, e.g. pits on the
walls and sculpturing of spores. This quot;may be due, however, to the fact of the English slides having been cut
from chosen material.

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Table B.: Geographical distribution of coall-ball plants. The first group of columns contains continental
localities from the Finefrau-Nebenbank Seam, the second the English ones. The Finefrau-Nebenbank column
IS a compilation of the species found till now on the continent. The last group contains the localities from the
German Katharina Seam.

GEOGRAPHICAL DISTRIBUTION. - I„ table B I have collected all data regarding the distribution
of coal-ball plants I have been able to gather from the literature and from the catalogues of the U t r e c h t,
Amsterdam, G r o n i n g e n, H e e r 1 e n, Liège, and Manchester collections of slides. It is very
unfortunate chat these data are not always reliable. Several times I have met with slides from the same
block, which, according to the label and the catalogue, were found in different localities! The only data which
can be rdied upon are those from the Dutch. German, and Belgian material. Nevertheless it is possible to state
that the flora of all locahties is very much the same. Thanks to the kindness of Dr. SusannE LeCLERCQ
and Prof. FraIPONT. who allowed me to examine the Belgian collection of slides from Bouxharmont. I
am able to compare more carefully the flora of this locality with the Dutch one. both of which are from
the same stratigraphical horizon, but about 25 Km apart (Table C).

Botryopteris cylindrica
Stauropteris oldhamia
Lyginopteris oldhamia
Lagenostoma ovoides
Medullosa anglica-Myeloxylon
Mesoxylon multirame
Lepidodendron vasculare
Lepidodendron Hickii
Lepidophloios laricinus
Lepidophloios macrolepidotus
Lepidostrobus oldhamius
Sigillarian leaf-bases

In this table I have mentioned only those species, which are common in one of them, and absent or very
rare in the other. Of the Belgian balls about 1000 have been cut; of the Dutch material about 200 have been
examined, thirty of which were investigated only superficially. There is no doubt that in composition these
floras differ slightly, but this difference is comparable with that existing in many cases between two parts of
the same moor in modern times. As yet it is impossible to state definitely the origin of this difference, but
it is due in all probability to some oecological reason.

TECHNICAL REMARKS. - All slides have been cut and ground by the author. Although this has
taken a considerable amount of time, he thinks it advisable that every student of this subject should take the
trouble to do so. Only by observing every stage in the preparation of each slide, is it possible to gain a satis-
factory insight into the way in which these fossil plants are built up. The method of grinding slides is very
easily learned, and the time spent in grinding is regained while examining the sections.

The photographs have been taken by the author. The best results he has got with orthochromatic ultra-

rapid press plates „Argusquot; (H 6 D 700). made by the
N. V. Photax of Soest, Holland. The lens used in nearly
all cases is the lens of his photographic camera — a
Doppelanastigmat Unofocal. 1 : 6.8. f = 10.5 cm,
Steinheil, Muenchen. No intricate camera was used —
a simple magnifying apparatus constructed by himself
for negatives complied with all requirements! Text-
figure 1 shows its construction. Inside a hght-tight
box the slide is illuminated by an opal-glass electric
bulb of 200 candle-power. The slide is put on a
drawer with an opening in the centre. The camera
is attached to a second drawer by means of a plate-
holder, the bottom of which has been cut out. The
whole box can be moved up and down by means of
a pulley and a counterpoise in order to secure diffe-
rent magnifications. The image is focussed on a piece
of paper, lying on the table, which after focussing
is replaced by the nlate

f .he Utrech. Bc.an.cal Museu., whose lectures on Systematical Botany have kindled ,„ .e .he desire 1
do son,e research on .he origin of .he present-day land-flora, who has allowed n,e to choose . i Palaelo.
n,cal su ,ect for n,y Bo.anical .hesis, and who has shown great interest in the results of „y iTltt
ever-ready assistance and advice, I am grea.ly indeb.ed to hin,. To Dr W I lONrM.Kl 1 .
grateful for the kindness with which he has placed .his splendid material at ^y iispnbsp;LT ^^^\'

- by his advice in many doubtful cases, .he liberality with which he has perm tlTl to u
of books and reprints on this subject, many of which I could not have procu^nbsp;o.hnbsp;TT

permission .o illus.ra.e this article as fuUy as the rich harvest of speci deTe v s My thlnr\' ^ H
.o the directors of the D o m a n i a 1 e M i, n, Mr. W. HUSMAN and ,r. H W SchAEBeT fquot;^
faclmes in collecting material and for perm.ssion .o publish ,he results of my
quot;gt;uch .ndebted .o Professor Dr. L. RuTTEN of Utrecht for permission to u^e The u . .
apparatus of the Mineralogical and Geological Museum, whil has a Id I : I :7asquot;many^^
as I deemed necessary. For hospitality at several laboratories and permission .o examine col . ,
.o thank Professor GHO.CE H.CKUKC and Dr. D. A. Aua^ of N e w c aTtTe 1 quot;r^G
now of Liverpool, Dr. G. H. CARPENTER and Mr. I W lACKSON of th K. ABSALOM,
Museum, Professor B. B. WeisS and Mr. ,0H. .Wa.™. of\'the M a^n^r. el

Professor C. FraIPONT and Dr. SUSANNE LeCLERCQ of L i e g e. Professor Dr. Th. STOMPS of Am-
sterdam, Professor Dr. J. C. SCHOUTE and Professor Dr. J. H. BONNEMA of G r o n i n g e n. In addition I
We to thank Professor PAUL BERTRAND of L i 11 e and Professor A. RenieR of B r u x e 11 e s for their
bndness in examining several of my shdes. In conclusion I am much obliged to Drs. J. S. H. BoERSMA

of Amsterdam and to Dr. douglas a. allan of Newcastle for their helpful criticism of the
nngiish ot my memoir.

The data regarding the species from the F i n e f r a u - N e b e n b a n k Horizon in colliery Rhein-
preussen (near Duisburg) and the Katharina Horizon in colliery Maria (Basin of Aix la
Chap eile) are based on slides and specimens in the collection of the quot;Geologisch Bureau voor het Neder-
landsche Mijngebiedquot; at H e e r 1 e n. The catalogue of this collection will soon be published

England: Bradshaw, Dulesgate, Halifax, -Shore, Stalybridge.
DUTCH MATERIAL. — Slides 144/0/1-3, 144/8/1-10, 144/9/1-10, 144/13/1-13.

DESCRIPTION. — Two specimens of this species have been found in the Dutch material, both in
coal-ball 144. In other balls isolated pieces of bark with adherent leaf-bases have been met with. At fkst I did
not know with what species to identify these stems, but in looking through the Manchester collection of
slides I met with a slide numbered R 1015 and labelled: ..Lepidophloios laricinus. Identified D. M. S. W AT-
SON. See block. WlLD collection of Blocksquot;, which whithout any doubt is identical with my specimens I
learned from a note in the catalogue, that this block (No. 1578) showed the surface-markings of Lepido^
phloios laricinus Sternberg. Thanks to the Museum Authorities, who kindly allowed me to borrow this block,
I am able to give a photo in my figure 12. I am indebted to Dr. IoNGMANS for confirmation of the identification
by Dr. Watson. The ball had been cut into three pieces previously. The section in the Manchester collec-
tion has been cut along the oblique plane (see fig. 12). It shows the beautifully preserved xylem in transverse
section. The structure of the leaf-bases is only moderately clear and the middle and inner cortex are not pre-
served. My description of this species is based on the Dutch material and on several slides from the Man-
chester and Heerlen collections, the numbers of which are appended.

MEDULLA. - The pith (fig. 5, 6) is composed of an irregular mass of parenchyma. Many cells not
only towards the edge of the pith but also in the centre, are divided by one or more walls. In longitudinal
section the medulla is seen to consist of elongated parenchymatous cells arranged in vertical rows. These
cells are separated by horizontal walls, but secondary oblique and even vertical walls also occur.

XYLEM. — The wood consists of a continuous ring of scalariform tracheides. The main body is about
4-6 tracheides broad, but on the outer side these large ones give place to a narrow belt of much smaller
tracheides. This belt is usually one, sometimes two, tracheides broad. The protoxylem-points form a beau-
tifully developed corona (fig. 5, 6). They, consist of triangular groups of 20-30 tiny tracheides. At the base
i-e. at the surface of the metaxylem, the triangles approach one another. I have ground very carefully some
shdes tangentially up to the xylem (fig. 11) in order to decide, in what way the protoxylem-ridges are dis-
tnbuted on the surface of the metaxylem. C. E. bertrand. in his excellent monograph on Lepidodendron
Marcourtn (1891), states that the ridges spht open while giving off a leaf-trace, and that the halves fuse
With those to the left and to the right, forming a prominent network. This opinion is based on the study
o transverse sections only. seward (1910, p. 163). however, figures a small piece of a tangential section
ot Lepidodendron fuliginosurn and states that the protoxylem-ridges run in vertical lines and do not form a

network. ScOTT (1920) mentions both opinions but does not definitely support
either. Of course BerTRAND\'S statement refers to Lepidodendron Harcourtiu but
I am not convinced that he has used the true Lepidodendron Harcourtii. In Man-
chester I have seen slides cut from Halifax Hard Bed material and identical with
those figured by BerTRAND. who does not, however, state the origin of his slides
SEWARD\'S statement refers to Lepidodendron fuliginosum. but as in transverse sec-
tions It IS impossible to distinguish the xylem of my species from that of the L Har-
courtti figured by BerTRAND and of L. fuliginosum, I thought it worth while to
investigate my material most minutely. A careful study of my slides has convinced
me that BertRAND was right: the ridges form a network with very long and
narrow meshes. I have not seen the slide from which SewARD has formed his
opinion, but I think it highly probable that the piece of stem cut tangentially was
either too short or was not cut exactly in the right plane. Figure 11 and textfig. 2
show part of the section in which the fusion of the ridges is shown most clearly.

LEAF-TRACE. — The mesarch leaf-traces are formed inside the protoxy-
lemndges (fig. 6). When these have split open as described above, at first the
traces remain parallel to the xylem, and then pass very gradually outwards, assu-
ming an almost horizontal course about halfway to the leaf-bases

laridnus, showing .he „«-nbsp;Museum collection is a slide, numbered R 284, and labelled Halonial

, ,nbsp;JONGMANS there are two independent slides, numbered 221 and 222 and labelled

L AMSON (XI, f,g. 9) and cop.ed by SEWARD (19.0, fig. 172) and ScOTT (1920, fi,. 72) as this is a s, m
of Up,dodendro„ Hickii cut somewhat obliquely. (Compare fig. 29).nbsp;■ 9 »nbsp;stem

leaf-base. _ As to the form and structure of the leaf-bases I refer to my figures 1-4 7-10 which
also clearly show the ligula. the ligular pit. the vascular bundle, and the parichnos Th base o the

Yf^ti bUDES. - I regard the following slides as belonging to this species:
a: the slides of the D u t c h material mentioned above

c: Slides in the He erl en collection: 218-220.221/1-6,222,223/1-5.
d: Slides in the G r o n i n g e n collection: G 74-79.

1893-1. Po to nie, Zeitschr. Deutsch. Geol. Ges., XLV, p. 330.
1893-2. Potonie, Ber. Deutsch. Bot. Ges., XI, p. 319-326, Taf. XIV
1899. Potonie, Pflanzenpalaeont., p. 235, figs 223-224.
Lomatophloios macrolepidotus (Goldenberg) Corda.

1881. Weiss, Zeitschr. Deutsch. Geol. Ges., XXXIII, p. 354.
1890. Seward, Proc. Cambr. Phil Soc., VII, (1890) 1892, p. 43, Pl. HI
1908. B o w e r, Landflora, p. 305.
Lepidophloios laricinus Lomax (non Sternberg).

1910. Seward, Fossil Plants, II, fig. 146D.
DISTRIBUTION. — Hör. - Finefrau-Nebenbank.

Ut,b(.KlF110N. — Figure 91 shows the surface of a beautiful soecimen ofnbsp;u, ■

a.3ch B„eau voo. He. Nede.a„dscHe Mii„«eb,ed a. Hee.len. As shown by sectionsnbsp;;

h,s s em .s ,n all „specs identical with .„o s,e.s f.o. .He Du.cH „a.erial. All ,He o.Her pHo.og.ap
been ,a en fcon, .He Du.ch s.e„s wi.H reflec.ed ligH. .He e.cHed surface o, polished slabs . v !
cunous .ha. .H,s s.e„, which is fairly abundan. bo.H in .He EngHsh and .He Dn.ch coai-balls occl v
rarely as an .„pression. Till now it has no. been found as such in Du.ch LimburgInbsp;\'

of figure 91, which can also be found in (He Heerlen collection. (Fig 91 bis) The nrotov , quot;
type of that of £ep«op/,/o,-o. ,a„c,„„s, a well-developed corona being presentnbsp;\' \'

In none of the Dutch specimens, in which the xylem is shown the nrotoxvlem H» k
The metaxylem of one of the Dutch specimens (fig. 90) Lnsists of a co lapsed IgTf cheT \'\'T .
el^en. br^^ wh.ch now has a len,h of abou. S cm. so that .He diamLr^TL^^rr

LEAF-BASE. - As .0 .He form and s.ruc.ure of .He leaf-bases, I refer lo mv fiaures n 1 ■ ■
show .He leaf-base cut in three directions and in several planes. PHo.ograpHs 23-26\'hat been ^ntn\'
ano,her specimen, in which .he lower half of .he leaf-cushion has developed a knob which quot; ta ,
section is shown as a separate structure. The leaf-.race and the parichnos pass horLontal hro quot; H
™r.ex, but in .He leaf-base .Hey bend downwards parallel .0 i.s under Lrface No ale 7nbsp;T quot;

rriiMuibb. - By several authorities on impressions the possibility is mentioned .ha.nbsp;■

phloios laricinus. and which can only be reconciled by supposing considerable growth in length of the leaf-

bases. As tdl now no facts have been discovered supporting this supposition. I cannot accept the theory that

Lepidophloios laricinus and Lepidophloios macrolepidotus represent one form, and I therefore regard them as
two quite independent species.

1911.nbsp;Zalessky, Etudes paleobot.,I, p. 1. figs H-15.
1920. Scott, Studies, 3d Ed., I, p. 120.

1927. Koopmans. Jaarverslag 1926. p. 50.
Lepidodendron Harcourtii Williamson (non Witham).

1881. Williamson, On the organization etc., XI, p. 288, fig. 9.
1889. Williamson, On the organization etc., XVI, p. 196, figs 1 -6.

1893. Williamson, On the organization etc., XIX. p. 1. figs 1-2B, 4, 6. 8-14. 16-21, 26-29*.

1894.nbsp;Williamson, Proc. Roy. Soc. London. LV. p. 422.
Lepidodendron fuliginosurn Williamson.

1887. Williamson. Proc. Roy. Soc. London, XLII, p. 6.
1893. Williamson. Index. II, p. 13. (pro parte).

1910.nbsp;Seward. Fossil Plants. II, p. 153. fig. 172.
Lepidodendron obovatum Zalessky (non Sternberg).

1911.nbsp;Zalessky, Etudes paleobot.. I, p. 10.
1927. Hirmer, Handbuch, I, p. 219.

1872. Binney. Observations. Ill, p. 89. PI. XVI, figs 1-5, PI. XVII figs 1-6
DISTRIBUTION. - Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale Mijn.
Germany: Rheinpreussen.
England: Dulesgate, Stalybridge.
DUTCH MATERIAL. - Slides 13/1/1-2, 13/2/1-3. 13/3/1-7, 67/0/1-2, 78/0/1, 148/0/1. 148/2/1

DESCRIPTION. — The Dutch specimens are all about twice as big as the English type-specimens

m the Manchester Museum collection. The diameter averages 3 cm against ± 1,5 cm for the English
specimens.

MEDULLA. — The pith is composed of an irregular mass of parenchyma (fig. 28). Nearly every
cell towards the edge of the pith is divided by one or more walls. In longitudinal section the pith is seen to
consist of elongated parenchymatous cells, arranged , in vertical rows. These cells are separated by horizontal
walls, but secondary oblique walls also occur.

XYLEM, — The wood (fig. 28) consists of a continuous ring of scalariform tracheides of fairly

uniform size. 4-6 elements broad. On the outside these large tracheides give place to a narrow belt of much
smaller tracheides. which is only 1 or 2 tracheides wide. The protoxylem points consist of small groups of
tracheides. which seldom project more than two tracheides and do not form a corona.

MIDDLE CORTEX. — Where preserved it is composed of parenchymatous cells, which form a
spongy mass.

PERIDERM. — One. perhaps several layers of phellogen are present, but as the preservation is bad
nothing can be recognized with certainty.

LEAF-TRACE. — The leaf-trace immediately after leaving the wood of the axis (fig. 28) is a small
mesarch bundle of about 10 or 12 tracheides. Their further course could not be followed.

LEAF-BASE. - The cushion has the form of a truncated rhombic pyramid, measuring about 6 mm
horizontally. 5 mm vertically, and projecting about 4 mm from the surface of the stem, (figs 27 29 32)
The vascular bundle enters the leaf-base almost horizontally at about of its height, and passes\'straight
on to the leaf-scar. The ligular pit begins at about the centre of the leaf-base and runs upwards in an obhque
direction at an angle of 45quot;. The structure of the ligula is not preserved. The base of the ligula received an
abundant supply of transfusion tracheides. The parichnos is first seen as a single strand of parenchyma imme-
diately below the vascular bundle. Soon this strand divides into two, which gradually diverge towards the

outside, till they communicate with two depressions on the lower surface of the cushion, which are filled with
a typical aerenchymatous tissue (figs 27 30)

BRANCHING OF STELE. - This has been observed in blocks 148 and 168. It seems to be of the usual
Halonial type, a small portion of the xylem separating off and passing out.

LEAF. _ No leaves have been found in organic connection or associated with the stem.

19-27. H i r m e r. Handbuch, I. p. 222. [Lepidodendron fuliginosurn Hirmer (non Williamson) 1
b: specimen of ZALESSKY.

1912.nbsp;Zalessky. Ibid, suppl., p. 17. figs 1, 5-9.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

bee d^^\'I^fDESCRIPTION. - See above: ZALESSKY 1911. The specimen of ScOTT has not yC
been described extensively.nbsp;^

description. _ In coal-ball 167 is contained a Upidodendrc. the leaf-bases of which are also
how on the outer surface of the block ,fig. 48). Although the external tissues are missing, their formt
yp.cai ^ough to warrant identification with Lepidodendron obcatum Sternberg. This identification is con-
hrmed by the study of sections of not-exposed leaf-bases. Of the xylem many remains are present, which
howeyer, are .solated owing to the crushing and do not form a continuous ring

XYLEM. _ The xylen, (fig. 89) is of the type of Lepidodendron Hickii. a metaxylem of rather

large tracheides, on the outer surface of which a number of narrow elements represent the protoxylem This is

not developed as a corona, being only slightly crenulated. The total measurements before crushing cannot
be ascertained.

CORTEX. — The soft tissues between the xylem and the outer cortex have all disappeared

LEAF-BASES. - The leaf-bases are about 13 mm broad, 22 mm high, and 7 mm thick. The
vascular bundle, the parichnos, and the ligular pit are directed obliquely upwards. The parichnos communi-
cates w,th two well-developed masses of aerenchyma. The keel of the leaf-bases is furrowed by several hori-
zontal grooves. which, however, are less in number and further apart than in Lepidodendron aculeatu,n.
F,gs 34-50 give an idea of the different forms the leaf-bases may assume in different planes of section.

1927. Hirmer, Handbuch, I, p. 222. [Lepidodendron [uliginosum Hirmev {non WiWiamson)]
b: Specimina I and II ofZALESSKY.

1909. Zalessky, Mem. Imp. Russ. Mineral. Soc., XLVL p. 283, PI. IV-VII 3 textfias
DISTRIBUTION. - Hor. - Finefrau-Nebenbank.nbsp;\'nbsp;\'

England: Shore.
DUTCH MATERIAL. — Coal-ball 166.
EXTENSIVE DESCRIPTION. - See above: zalessky 1909.

DESCRIPTION. - In coal-ball 166 is present the flattened stem of a Lepidodendron. The periderm
and the leaf-bases are well preserved, but of the xylem only small fragments can be traced. No transparant
shdes of this stem have been ground, as the structure can be observed very well on the etched surface of
polished slabs. The photographs also have been taken with reflected light.

XYLEM. - With regard to the structure of the xylem. nothing can be learned from the literature
seward (1906) has described a specimen, in which the woody cylinder shows the characteristics of Lepido-
dendron ..fnhginosumquot;, i.e. a well-developed corona. Unfortunately in his specimen neariy all the tissue of
the leaf-bases has been lost, as shown in the photo of a transverse section. I n m y o p i n i o n h i s s p e c i-

men may belong as well to Lep/cfopUo/os rn a c r o I e p i d o t u s as to Lcpidodcn-

dronaculeatam. (Compare figs 23 and 53, both of which have been cut in the plane by which SeWARD\'S
specimen is limited.)

Zalessky (1909) has described two .specimens, in the first of which the wood is preserved but the
second consists only of the periderm and the leaf-bases. I am not convinced, however, that these two specimens
belong to the same species. Specimen II is in all respects identical with my specimen. The form of the
leaf-bases of specimen I in transverse section is very curious, being bladder-like and swollen; in radial
section then upper part hangs over somewhat, resembling an underdeveloped Lepidophloios (ZaLESSKY
1909, PI. IV, figs 5 and 9.). The ligular pit, the leaf-trace, and the parichnos of specimen I are curved ending
m a downward direction, while in specimen II and in my specimen they are straight, having a course directed
steeply upwards. According to zalessky the surface of the block showed the leaf-bases of Lepidodendron
aculcatum. The figure, which ought to prove this, is unfortunately not very distinct (ZalESSKY. 1909, text-

f.g. 1). At present I cannot regard ZALESSKY\'S specimen I as identical with
Lcp^dodendron aculeaturn Sternberg and even I should not wonder if addi
t.onal material should prove its identity with L e p i d o d . n d r o n J a r . c z e u. s k i,
Zedier. Therefore his description of the xylem cannot be used in describing the structure oi Lepidodendron
aculeaturn and so it is impossible as yet to postulate with certainty the presence of a corona or the develop-
ment of the protoxylem as in Lepidodendron Hickii.

LEAF-BASE. - The leaf-bases are about 30 mm high, 10 mm broad, and 5 mm thick. The leaf-

ocatnce .s placed at about a third of the distance from the top. The vascular bundle, the parichnos and the

hgular pit are directed obhguely upwards. The parichnos communicates with two well-developed masses of

aerenchyma. The keel of the leaf-base is furrowed by several horizontal grooves, simulating in tangent an

radial sections a number of thorn-like projections. Figs 51-60 give an idea of the different forms the e^f bas
may assume in different planes of section.nbsp;leat-base

1921.nbsp;Potonié-Gothan, Palaeobot., p. 206.
1927. Koopmans, Jaarver.slag 1926, p. 50.
1927. Hirmer, Handbuch, I, p. 230.

1925. Leclercq. Mém. in 4« de la Soc. Géol. de Belg., VI p 40 PI XXI XYTX/ f , ,
Lepidostrobus sp.nbsp;^ \'nbsp;^^l\'XXIV, figs 11-16.

1886. Felix, Abh. Geol. Spezialk. Preussen. VII. 3, p. 35, Taf IV fiqs 1 3
Leptdocarpon sp.nbsp;^

1871. Binney, Observations, U, p. 46, PI. VII, figs 1-5, 7-io
Lepidodendron vasculare Binney.

dutch material. - SiHes 28/,/,-5, 28/2/,-,. 28/3/,-2. 28/6/,, 28/,3/,-2, ,02/2/,-3 ,3,/0/, 7
dhIc™Onquot;\'X™nbsp;- AC. arbk. ...

iJlibCKlPTION. — The material from coal-ball 28 consists of fnnr ..roK-P , ac. .
have an average diameeer cf about 2 c. w.h an a.s of about 3 n,. quot;nbsp;tL\' oquot;, t h M

XYLEM. - The xylem consists of a ring of tracheides enclosing a medulla Whether the nrnt 1
forms a corona or not, I could not determinenbsp;Whether the protoxylem

SPOROPHYLL-TRACE. - The sporophyll-traces branch off from the outer surface of the . I
the passage to the oedice, of rhpnbsp;i,nbsp;,nbsp;quot;nbsp;^nbsp;quot;^rk

It broadenrnbsp;u quot; P = = quot;gt;as an a,most triangdar outline when seen in tangential section

be ascertained \'nbsp;\'\'quot; ^nbsp;\'\'^»-ns and form in vertical direction could no,

two beautifully preserved slides (H5/2/1 2 Un ^nbsp;f^^^^nbsp;P- 208) can be observed in

1914. A. Arber, Trans. Linn. Soc. London. (2). Bot, VIll, p. 21\'0.
1920. Scott, Studies, 3d Ed., p. 167, figs 79-80.
1927. Hirmer, Handbuch, 1, p. 230.
Lepidostrobus sp.

1893-1. Williamson, On the organization etc., XIX, p. 27, fig. 57.
1893-2. Williamson, Index, II, p. 123.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale Mijn.
England: Hahfax.
DUTCH MATERIAL. — Slides 40/6/2-3.
EXTENSIVE DESCRIPTION. — See above: Maslen 1899.

DESCRIPTION _ The preservation of the Lepidostrobus contained in the above-mentioned slides

(fig. 71) is very poor. As the oblique direction of the sporophylls and the form of the free laminae quite agree
with the figure published by MASLEN. I think it highly probable that this Lepidostrobus is identical with
Lepidostrobus foliaceus Maslen. Better preserved specimens are necessary for definite identification.

1914. A. Arber, Trans. Linn. Soc. London, (2) Bot., VIH, p. 212, figs 4-8, 18-30.

England: Locality unknown.
DUTCH MATERIAL. — Slides 40/0/1-2, 40/2/2-7, 40/3/2.
EXTENSIVE DESCRIPTION. — See above: A. Arber 1914.

DESCRIPTION. — The general structure of the cone is the same as in Lepidostrobus oldhamius.
Some peculiar features shown by this specimen make it possible to refer it to Lepidostrobus Binneyanus. The
cone is remarkably slender, about 1,5 cm in diameter, as far as it is possible to measure the badly crushed

XYLEM. — The vascular cylinder of the cone axis is nearly solid (fig. 75). Only a very small opening

in the centre probably represents the pith. A protoxylem corona I could not observe.

SPOROPHYLf -TRACE. — In one ot the leaf-traces the oblique downward direction in the distal
portion of their course from stele to sporophyll can be observed (fig. 73). Very remarkable are the large
gaps in the outer cortex through which the leaf-traces pass to the pedicel. On account of these gaps the
leaf-trace is never enclosed by cortex tissue in transverse sections as is the case with Lepidostrobus oldhamius.

SPOROPHYLL. — The pedicel has a well-developed keel. The large-celled hypoderma described by
Dr. Agnes Arber could not be recognized with certainty. The sporangium is attached to the pedicel by a
stout ridge of tissue (fig. 74), possibly containing transfusion tissue. On either side of this ridge a cushion-
like ridge of sclerosed tissue is present. The pedicel is provided with wings which embrace the sporangium
to about half its height (fig. 74). The limb of the sporophyll is rather \'large. Owing to the crushing I could

AFFINITIES. — In several features the cone strongly resembles the strobilus of Lepidocarpon Lomaxi

Scott (1901). Without laying undue stress on them, I would point out the following concordant characters:
a: the distinctly developed keel of the pedicel;
b: the ridge by which the sporangium is attached;
c: the ridges of sclerosed tissue on either side of the median line;

d: the wings of the pedicel, which closely resemble the integument of Lepidocarpon Lomaxi.

1921.nbsp;Po tonjé-Gotha n, Palaeobot.. p. 236, fig. 197.
_ 1927. Hirmer, Handbuch, i, p. 328, figs 388-392.

1925. Leclercq, Mém. in 4« de la Soc. Géol. de Belg., VI, p. 41, PI. XXV, figs 17-19
ly^/. Koopmans, Jaarverslag 1926, p. 51.
Cardiocarpon anomalum Williamson (non Carruthers).

1900. W i 1 d and L o m a X, Ann. of Bot., XIV p 160
DISTRIBUTION. - Hor. - Finefrau-Nebenbank.

England: Dulesgate, Halifax, Oldham, Shore, Stalybridge, Strinesdale
/ior. - Katharina.

extensive description. - See above. SCOTT 1901
ana ^ quot;quot;sT;?olmnbsp;^ ^ — 9.1,

.he sporangium surrounding .he megaspore, and .he megaspore wall are all clearly shown

l-.g. 79 shows .he second section from .he bo.tom of a series of four c,„ f__\' j ■ .

Fig. 77 shows a seed in naked condition. As yet the integument is only represented by two pads of dark
tissue at the base of the sporangium. The megaspore wall is very distinct.

1886.nbsp;Felix, Abh. Geol. Spez. Karte Preussen, VII, 3, p. 38, Taf. V, fig. 1.

1887.nbsp;Solms-Laubach, Einleitung, p. 277, figs 32-36.
1887. Williamson, Monograph, p. 1, PI. IV-XI.

1900.nbsp;Seward and Hill, Trans. Roy. Soc.Edinb., XXXIX, p. 910.
1900. Zeiller. Paléobot., p. 201.

1925. L e c 1 e r c q, Mém. in 4quot; de la Soc. Géol. de Belg., VI, p. 45, Pl. XXVI : 1-2, XXVII : 4,

XXIX : 6-7. XXXI : 9. XXXII : 10, XXXIII : 11.
1927. Koopman s. Jaarverslag 1926, p. 50.
1927. Hirmer, Handbuch. I, p. 290, figs 342-348.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale Mijn.
Germany: Rheinpreusen.
Belgium: Bouxharmont, Jupille.

England: Bacup, Deighton, Dulesgate, Oldham, Shore.
Hor. - Katharina.
Loc. - Germany: Vollmond.
Stigmaria-appendices: everywhere.
DUTCH MATERIAL. — Slides from coal-balls 12, 26, 53, 54, 60, 140.
EXTENSIVE DESCRIPTION. — See above: williamson 1887, ScOTT 1920.
DESCRIPTION. — I shall describe all subterranean organs with secondary growth of Lepidodendron
or Sigillaria found in my material as belonging to the collective species Stigmaria ficoides Sternberg. I think it
very possible that more species might be distinguished, but, as the differences are very slight, I shall join the
majority of the authors who have written on this subject using only this specific name. It is quite possible that
some of my specimens belong to Stigmaria bacupensis Scott (See LECLERCQ, 1925). but the description given
by Miss LECLËRCQ is too short to allow of a definite identification, nor has examination of the Belgian slides
enabled me to decide with certainty (Compare fig. 93).

MEDULtA. _ The centre of the stele was occupied by a fair-sized pith, of which only in some slides
traces have been found attached to the wood.

wood. The bulk of the xylem consists of radially arranged-, scalariform tracheides. In addition to the prinla
phloem and inner cortex are not preserved.

PERIDERM. - Periderm formation set in early. The first stage is seen in fig. 84 at the inner edae
rp\'pENOrcE;nbsp;omy .issue present ,fig. a\',;.

bundle, a dehcate mner cortex surrounding the wood, and an outer cortex, which some.imes is connected with

.he .nner cor.ex by a s.rand of parenchyma. Fig. 83 is a .angen.ial sec,ion of a main axis, showin sevi

pom. of .he ax,s. The parenchyma surrounding these traces represen.s the principal medullary ray.

u er cortex have been sclerosed. Sometimes these sclerosed cells form a ring on the inside of the outer cortex
In the above-mentioned slides, however, these cells form sclerotic nests, which are very regularly distribute Tnd

gat d. The number of cells in, each nest varies from 5 to 10. The structure of the xylem and of .he inner

rVhi \'nbsp;Stigmarian roo.le.. In a few ins.ances .he middle cor.ex has been preserved

een and a , to my knowledge, they have never been described or figured before, I consider it legitimate

and advisable to set .hem apar. as a separa.e species and to call them 5«,™ar,a arac.noiVfea. I have chosen

Z J T quot; \'\'nbsp;a- nndoub.edly fragmen.s of some Upl
d^endron or lepWopWoios. As I am no. convinced that .hey do no. belong .0 some species described befo-
IH. usmg the number of the coal-ball in which they are found as a means of referring to my specimens

DESCRIPTION. — Diploxylon 89 consists of a stem showing a great deal of secondary growth. Part
of the medulla, the primary and the secondary wood are preserved. The primary xylem is about 2 mm thick,

MEDULLA. — The pith (fig. 88), is poorly preserved. Some traces of cellular tissue are present.

As far as could be made out, this tissue was entirely parenchymatous without any isolated tracheides.

XYLEM. — While the protoxylem (fig. 88) is poorly preserved, it seems not improbable that a corona

is present, though less developed than in Lepidophloios laricinus. The metaxylem consists of a ring of large

scalariform tracheides. The main body is about 10 tracheides broad. On the outside, the large ones give place

to a narrow belt of much smaller tracheides. The secondary xylem (figs 87, 88) consists of very regular

radial rows of scalariform tracheides. Those quite near to the protoxylem are rather small, but they soon

become bigger, till their diameter is about the same as that of the metaxylem elements. Their oudine is almost

square. At several places the radial rows are interrupted by very curious groups of small tracheides (fig. 87.).

These groups do not represent leaf-traces, as in tangential section the latter are shown to consist of mesarch

groups of still smaller tracheides, which have apparently a strictly horizontal course. No free leaf-traces have

been observed. The numerous medullary rays are one cell wide and of variable height.

DESCRIPTION. — Diploxylon 144 consists of fragments of the wood and the periderm of a large
stem (fig. 85.). The complete measurements of this stem cannot be ascertained.

XYLEM. — Both primary and secondary xylem are present (fig. 86 ). The primary xylem consists of
a zone of large, scalariform tracheides, irregularly arranged, 3 mm thick, and about 13 elements broad. The
secondary xylem consists of a zone of somewhat smaller, scalariform tracheides, radially arranged, 5 mm thick,
and\' about 40 elements broad. The protoxylem is represented by small groups of tracheides, which do not form
a well-marked corona.

LEAF-TRACE._It is a curious feature of this stem that no leaf-traces have been observed, either in

PERIDERM. _The periderm (fig. 85) is the only tissue present outside the wood. It has been abun-
dantly developed and forms a zone of about 18 mm thick, consisting of small cells, which in transverse section
are about square, and in tangential and radial section somewhat rectangular. On the outside it has split up
into a great number of thin lamellae.

1927. Koopmans. Jaarverslag 1926, p. 50.
Compare also:
Sigillaria scutellata Brongniart.

1909. Arber and Thomas. Phil. Trans Roy. Soc. London, CC, p. 139 PI XIV
oigtllana mamillaris Brongniart.

1907. K i d s t o n, Proc. Roy. Soc. Edinb., XXVII, 3, p. 203, fig. 1.
Sigillaria Boblayi Brongniart.

England: Huddersfield, Shore.
DUTCH MATERIAL. - Slides 64/0/1-3, 64/1/1-2.
EXTENSIVE DESCRIPTION. - See above: KiDSTON 1905.

description. _ The Dutch specimen consists of a small portion of the woody cylinder with
which a piece of bark is associated. The coal-ball in which it occurs, is only a very small one so that there
IS no chance of larger remains being found in other slides from this ball

PRIMARY XYLEM. - The primary xylem (fig. 33) is about 0,8 mm thick. The outer surface is
strongly and regularly undulate, so as to form a number of blunt ridges alternating with as many furrows Th
jer surface of the primary xylem is undulate, too, but not as regularly as the outer surface. The main mass
of the primary xylem consists of large tracheides, more or less hexagonal in transverse section, and without
ustnbsp;P-enchymatous cells. They diminish slightly and gradually in size towards the outside, but

that the elements of the metaxylem are elongated, scalariform tracheides. So far as was observed, no spiral

renu ate outhne of the primary xylem, and the outer surface exhibits the same structure. The tracheides of

the secondary xylem are arranged in radial rows, interspersed at intervals with medullary rays, which run un-
nterrup ed y through the whole thickness of the secondary wood. Longitudinal sections of the stele show that
the tracheides of the secondary xylem are elongated and scalariform with pointed edges, similar to those of the
ma,n body of the primary xylem. but only somewhat smaller in diameter. The tracheides are of uniform size
throughout the secondary xylem, there being no difference between those opposite the ridges and those
opposite the furrows. At the ridges only the primary and the secondary xylem are in direct contact In the
furrows a black line intervenes between the primary xylem and the inner tracheides of the secondary xylem
This hne probably consists of collapsed thin-walled cells.nbsp;\'

urrows. When the lea -trace becomes free from the metaxylem it consists of a group of about a dozen small
racheides, arranged radially around the smallest of them. The structure is distinctly mesarch. By the time the
leaf-trace emerges from the secondary wood, one or two rows of tracheides have been added, mostly on the
^de near the axis. In leaf-traces, which are quite free from the axis, the number of tracheides is still greater
The course of the leaf-traces through the xylem could not be followed.

CORTEX. _ A piece of cortex was found associated with the wood. The only part of it which is
preserved ,s that formed by a portion of the ribs and the underlying periderm. In transverse section the peri-
derm consists of very small cells placed in radial rows. The main body of the rib consists of fairly thick-walled
parenchyma. In the cortex no leaf-traces are seen.

UbSCRIPTION. - In the above-mentioned balls isolated leaf-bases of Sigillaria are present. I have

not been able to decide with sufficient certainty to what species these remains belong. I think it probable that

Coal-ball 27 contains several layers of bark of a Sigillaria. On the outside of the ball the impression of
the leaf-bases is shown, (fig. 96.) According to Dr. W. J. jongivians this impression probably belongs to Si-
gillarta mamillaris Brongniart. (Compare deltenre 1926, PI. XIV.) Unfortunately no wood has been
preserved.

Associated with these leaf-bases are found Mazocarpon cf. shorense Benson (see below) and Sigil^
lariopsis laevis Koopmans (see below).

Loc. - Limburg: Domaniale Mijn,
DUTCH MATERIAL. - Slides 27/0/2-5. 27/1/1. 27/2/1-2. 27/6/1-6.

DESCRIPTION. — In coal-ball 27 numerous leaves are found closely associated with leaf-cushions
of Sigillaria mamillaris (see above). The preservation is not very good, but in all specimens the double vascular
bundle, characteristic of Sigillariopsis, is clearly shown (fig. 94). Only the xylem has been preserved, the
softer tissues, i. e. the phloem and the secretory tissue, having disappeared. The transfusion-tissue partly
surrounds the bundle, leaving a gap between the xylem groups as in Sigillariopsis sulcata. The main body
of the leaf consists of an irregular parenchyma, while, beneath the upper face traces of palissade parenchyma
are present. The only important differences with Sigillariopsis sulcata Scott (1904-1) are the total absence
of the stomatiferous furrows and the presence of a distinct keel on the dorsal face of the leaf. I, therefore, regard
the Dutch specimens as a distinct species and propose the name Sigillariopsis laevis, as the absence of the
furrows makes the surface quite smooth.

1920. Scott, Studies, 3d Ed.. I, p. 213. figs 103-106.
1927. Hirmer, Handbuch, I. p. 284. figs 333-335.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

England: Bacup, Deighton, Dulesgate, Halifax, Shore, Stalybridge.
DUTCH MATERIAL. — Slide 27/0/2 and many isolated spores in other slides.
EXTENSIVE DESCRIPTION. — See above: BENSON 1918.

DESCRIPTION. _ In many slides there are present isolated megaspores bearing a strong resemblance

to those published oi Mazocarpon shorense. The figured slide (figure 95) contains a sporangium, in which
four megaspores are seen. The sterile central pad consists of parenchymatic tissue. The sporangial wall has
been preserved but does not show any structure. Traces of a tapetum can be recognized.

This sporangium has been found closely associated with Sigillariopsis laevis (see above) and with leaf-
bases of Sigillaria mamillaris (see above).

1894. Williamson and Scott, Further observations, I, p. 920, photographs 19-22, figs

1925. Leclercq, Mém. in 4« de la Soc. Géol. de Belg., VI, p. 31, PI. XI, fig. 1, PI. XII, fig. 4.

1886. Felix, Abh. Geol. Spez, Karte Preussen, VII, 3, p. 42, Taf. VI, figs 1-7.
Asterophyllites sphenophylloides Williamson.

Loc. - Germany: Maria, Vollmond.
DUTCH MATERIAL. - Slides 27/0/1,4-11. 28/2/1 bis-2bis, 28/9/1, 102/1/1-2, 102/2/1-3, 102/3/2-3

DESCRIPTION. — The best preserved specimen is contained in coal-ball 27. It is found closely asso-
ciated with Sphenophyllostachys Dawsoni. (See p. 24) The xylem is beautifully preserved and is surrounded
by partly preserved periderm.

XYLEM. — The primary xylem. when seen in transverse section, is triangular (figs 100-104).
The sides of the triangle are somewhat concave, and the angles are slightly truncated. The xylem is a solid
mass of tracheides; there is no trace either of a medulla or of xylem-parenchyma. The tracheides near the
middle of the stele are of large size, but towards the three prominent angles their size rapidly diminishes, and
at the extreme ends the elements constituting the protoxylem are of very small diameter.

Secondary xylem. - As there is a distinct difference between the wood formed between the
protoxylem groups and that which is formed opposite them, I shall use the terms proposed by WILLIAMSON
and SCOTT (1894) viz.: i n t e r f a s c i c u 1 a r and f a s c i c u 1 a r wood. The large elements of the inter-
fascicular wood, which in transverse section appear to be almost square, often having truncated corners are
arranged in straight radial rows. Their radial walls are marked by numerous small pits. Between the corners
of the tracheides parenchymatous cells are found, occupying the space left by their truncated corners. Occasio-
nally one of these cells appears in each space in transverse sections; more often they occur in small groups
As is seen in tangential section, these parenchymatous cells, which form longitudinal strands of considerable
length, are connected by isolated cells with a radiate arrangement. The elements of the fascicular wood are also
arranged in regular rows, which, however, diverge fan-wise from the protoxylem groups. Nearer to the edge
of the wood their course becomes radial. It is sharply differentiated from the interfascicular wood by the much
smaller dimensions of the elements. This distinction, however, tends to disappear in the outer part of the wood

According to WILLIAMSON and SCOTT (1894) real medullary rays are present, but I have not been able to
verify this in my shdes.

WILLIAMSON and SCOTT (1894) suggest the possibihty that the secondary wood consists of real
vessels and not of tracheides. SCOTT in 1920 simply states this as a fact, and with this I do not agree. In

not a single longitudinal section remains of transverse walls have been observed as yet. The study of a series
of five consecutive transverse sections has shown some very remarkable radial walls, which are only to be
accounted for as sections of a very oblique wall, i.e. the wall between the pointed ends of two tracheides.
Figs 100-104 give an idea of the way in which these walls change their place in successive sections. I, there-
fore, think that the secondary wood also consists of pointed tracheides of considerable length, which are

SOFT TISSUES. — In several slides the wood is surrounded by some layers of small cells arranged
radially, which probably represent the periderm. The preservation does not allow of a description of any value.

Loc. - Limburg: Domaniale Mijn.
Germany: Rheinpreussen.
DUTCH MATERIAL. — Slides 40/0/6-9.

DESCRIPTION. — The general structure of this stem (fig. 99) closely resembles that of 5p/zenop%/-

a.nbsp;The difference in size between the masses of primary xylem: The distance between two protoxylem
groups in this species is only 0,4 mm, whereas it is more than 1 mm in the figures .of Sphenophyllum

b..nbsp;The surface of the metaxylem is less concave than in Sphenophyllum plurifoliatum.

c.nbsp;The rows of the fascicular xylem are almost straight; the fan-like divergence is practically non-existent.

d.nbsp;The earliest formed cells of the interfascicular xylem are much smaller than in Sphenophyllum pluri-
foliatum.

Comparison of figures 99 and 104, which are both magnified 25 times, clearly shows these differences,
which seem to be sufficiently important to justify specific distinction.

Sphenophyllum sp. 1927. Koopmans, Jaarverslag 1926, p. 51.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Hor. - Katharina.
Loc. - Germany: Maria.
DUTCH MATERIAL. - Slides 145/0/1-4. 145/1/1. 145/2/1-4. 155/4/1-4.

DESCRIPTION._The general structure of this species (fig. 98) agrees closely with that of Spheno-
phyllum plurifoliatum: a triarch primary wood enclosed by a zone of secondary xylem. The structure of the
medullary system is identical. There are no medullary rays but clusters of cells occur at the corners of the
secondary tracheides.

The most important character of this new species is the presence of canals in the protoxylem-region,
such as we know hitherto only from the Lower Carboniferous Sphenophyllum insigne. The discovery of this
occurrence in Coal-Measure species therefore constitutes a new record.

The second character in which this species differs from S. plurifoliatum is the fact that the diameter
of the metaxylem elements is much smaller in the new species.

The third distinction is that the outline of the primary wood is somewhat different: the arms are more
pronounced, and the central mass of tracheides is smaller than in 5. plurifoliatum (Compare figures 98 and 104).

The wood is enclosed by a ring of radially arranged elements, which are not well preserved. Probably
this ring represents the periderm.

As the presence of protoxylem-canals precludes identification with Sphenophyllum plurifoliatum, and as
the structure of the medullary system precludes identification withnbsp;msr^ne. I propose to recog-

1898.nbsp;Seward, Fossil Plants, I, p. 402, figs 107A-G, 108.
1910. Seward, Fossil Plants, II, p. 1, figs 112, 116.
1927. Hirmer, Handbuch, I, p. 355, figs 416-420.

1871. Williamson, Mem. Proc. Lit. Phil. Soc. Manch., V, p. 28, PI. I-III,
1874. Williamson, On the organization etc., V, p. 53, figs 28-30.
Bowmanites Dawsoni Williamson.

1893.nbsp;Zeiller, Mém. Soc. Géol. France, Paléont., No. 11, p. 5, figs A-G.
Sphenophyllum Dawsoni (Williamson) Williamson et Scott.

1894.nbsp;Williamson and Scott, Further observations, I, p. 933, photo 25-26, figs 54-58.
1897. Scott, Phil. Trans. Roy. Soc. London, B, CLXXXIX, p. 23.

1925. L e c 1 e r c q. Mém. in 4» de la Soc. Géol. de Belg., VI. p. 34, Pl. XII, fig. 5, Pl. XIII fiq 6

England: Bacup. Halifax. Huddersfield. Oldham. Shore. Stalybridqe
DUTCH MATERIAL. - Slides 27/6/1-5.

EXTENSIVE DESCRIPTION. - See above: WILLIAMSON and ScOTT 1894.
DESCRIPTION. — The specimen consists of a small part of a strobilus about 1 cm long which is
cut into five successive almost tangential slides. The section figured is the middle one and nearly radial (fig
97). Five whorls of sporangia are present. In the figured slide the lowest is represented by one sporangium
only. As the ball in which the specimen was found is very badly pyritized, the preservation is not good The
axis and the sporophylls are represented for the greater part by a structure-less mass, in which here and there
traces of tracheides and parenchyma can be recognized. Of the sporangiophores, nothing is left which can be
recognized as such with certainty. The sporangial wall consists of one row of small cells. The sporangia are

filled with a dense mass of badly preserved spores. The characteristic sculpturing of the spore-membrane has
disappeared, only the prominent spines are preserved in -some of them.

I am not sure whether this specimen represents the « or the ^ form of SCOTT (1920). or whether
it may be a y -form, as it is narrower than the « -, but broader than the ^-iovm. The preservation does not

The strobilus is found closely associated with the stem of Sphenophyllum plurifoliatum (see pag. 21.

DESCRIPTION. — In several slides small roots are found, which agree closely with the descriptions
and the figures given of the root of Sphenophyllum. As in all specimens the preservation is not good, it is
deemed unnecessary to give a description or a figure. In addition no other root exists for which it might be
mistaken and identification with a definite stem of Sphenophyllum is impossible, as it is found associated with
all three species of Sphenophyllum present in the Dutch material.

1898. Seward, Fossil Plants, I. p. 312, figs 74A. 75-76.
Calamodendron commune Binney (non Ettingshausen).

1868. Binney. Observations. I, p. 19. PI. II-HI.
Arthropitys communis [Binney (non Ettingshausen)] Renault.

1894.nbsp;Williamson and Scott. Further observations, I, p. 863, PI. LXXII-LXXIII.

1915. Jongmans. Fossilium Catalogus. Plantae. 5. p. 245. (Calamités communis), p. 418 (Cala-
mités species).
1924. Jongmans. Ibid., Plantae, 11, p. 769, 780.
On the leaves of Calamités (Calamocladus sive Asterophyllites) see:

1911. Thomas. Phil. Trans. Roy. Soc. London, B, CCII, p. 51, PI. III-V. 13 textfigs.
1920. Scott. Studies. 3d Ed.. I, p. 33, figs 12-15.
On the roots of Calamités [Astromyelon Williamsonis (Cash and Hick) Williamson] see:

1883. Williamson. On the organization. XII. p. 459, figs 1-14.
1886. Felix. Abh. Geol. Spezialk. Preussen, VII. 3. p. 48.

1871. Williamson, On the organization, I, p. 487, figs 16, 39.
1903. S top es, Ann. of Bot., XVII, p. 792, figs 30-32.
1908. Scott, Studies, 2d Ed., I, p. 41, figs \\5A6.
1920. Scott, Studies, 3d Ed., I, p. 39, figs 16-17.

1925. Led ere q. Mém. in 4quot; de la Soc. Géol. de Belgique, VI, p 25 PI III fiq 6

EXTENSIVE DESCRIPTION. - See above: WILLIAMSON 1871, WILLIAMSON and ScOTT 1894.
Compare also SEWARD 1898. ScOTT 1920.

DESCRIPTION. — Stems of Calamités are fairly abundant in the Dutch material. The structure of these
stems has been described several times, but there has been very little systematic investigation. Although I think

that several distinct species are present in my slides, I prefer to name them all provisionally Calamités com-
mams. My description will, therefore, contain only those characters in which they all agree.

MEDULLA. - The pith is hollow (fig. 105), except at the nodes, where a diaphragm is found
XYLEM. - Around the pith there is a ring of collateral vascular bundles. In place of the protoxylem
a gap is found, caused by the disorganisation of this tissue. The vascular bundles are separated by the prin-
cipal medullary rays, which are very wide in the vicinity of the medulla, but soon diminish in width. A layer
of secondary wood of varying thickness is present in all specimens.

ROOTS. - In several slides roots have been observed. They are distinguished from the stem by the
absence of protoxylem canals and the presence of a solid pith. It was not possible to recognize with certainty,
whether or not the primary wood is centripetal.

1869. Schimper, Traité, L p. 330, Ph XXIII, figs 5-10.
1874. Williamson, On the organization, V, p. 58, figs 33-43.

1881.nbsp;Williamson, On the organization, XI, p. 298, figs 23-27.
1881. Saporta et Marion, Evol. Crypt., p. 135, figs 55C-D.

1884. W e i s s, Steink. Calamarien, II, Abh. Geol. Spezialk. Preussen, V, 2 p 169 Taf XXI
fig. 7. ■nbsp;.....

1887.nbsp;Cash, Proc. Yorks. Geol. Polyt. Soc., IX, p. 449, PI. XXII, XXIII, XXVL
1889. Williamson, On the organization. XV, p. 160, figs 7-8.

1894. Williamson and Scott, Further observations, I, p. 901 PI. LXXIII-LXXIV fios

1900. Scott, Studies, p. 45, figs 16-22.
1906. F e 1 i X, Leitfossilien, p. 21, fig. 31C.

1909.nbsp;Thomas, New Phyt., VIH, p. 249, PI. I, textfigs 31-32.
1909.nbsp;Lotsy, Bot. Stammesgesch., IL p, 539, figs 361 : 1-3.

1910.nbsp;Hickling, Mem. Proc. Lit. Phil. Soc. Manch., LIV, 3, 17, p. 1. 1 Pl., 3 textfigs.

1925. L e c 1 e r c q, Mém. in 4quot; de la Soc. Géol. de Belg., VI. p. 26, Pl. IX. fig. 13. Pl. X. fig. 15.
1927. Koopmans. Jaarverslag 1926. p. 50.
1927. Hirmer. Handbuch. I, p. 401. figs 480-484. 488.
Volkmannia Binneyi Carruthers.

1869. Carruthers. Cryptog. Forests. Roy. Instit. Great Brit.. Weekly evening meeting 16

April, p. 7, PI. 11, figs 7-11.
1872. Balfour, Introduct. Palaeontol. Bot., p. 60, fig. 47 : 7-11.

1868.nbsp;Binney, Observations, I, p. 23, PI. IV-V.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

England: Dulesgate, Halifax, Huddersfield, Oldham, Shore, Stalybridge.
Strinesdale.

DUTCH MATERIAL. — Coal-ball 17, 28. 56, 76, 80, 91. 96, 98, 102, 127, and slides cut from these balls.
EXTENSIVE DESCRIPTION. — See above: WILLIAMSON and ScOTT 1894, HiCKLiNG 1910.
DESCRIPTION. — The strobilus is one of the commonest plant-remains contained in the Dutch mate-
rial (fig 107) Unfortunately the preservation is never very good. The structure of the xylem is shown in none
of the specimens, but still it is possible to recognize that it is triarch in some and tetrarch in others. The cone
consists of an axis to which are attached whorls of sporangiophores, alternating with whorls of sterile bracts.
The horizontal parts of the bracts are coherent, forming a disc. The vertical limbs are free. The whorls of spo-
rangiophores are midway between those of the sterile bracts, the number of the former in each whorl being
about half the number of the latter — as a rule they are six and twelve respectively. Each peltate sporangiophore
bears four elongated sac-like sporangia, which, in tangential section, surround the stalk of the sporangiophore.
Only microspores have been observed.

Loc. - Limburg: Domaniale mijn.
England: Oldham.
DUTCH MATERIAL. — Slides 89/0/5-6.

DESCRIPTION. - Slide 89/0/5 contains only the tips of some of the bracts. Shde 89/0/6 is a section
through the strobilus. partly radial, partly tangential. The general morphology of this strobilus is quite the same
as m C. Btnneyana, as is shown in fig. 106. It consists of an axis bearing whorls of sterile bracts and of fertile
sporangiophores. to which are attached four sporangia. The diameter of this cone, however, is twice that of
C. Btnneyana: 9-10 mm against 4-5 mm. This diameter and also the form of the bracts agreeing with the

text and figures of hick and LOMAX ( 1894). I think it highly probable that this specimen should be identified

1907.nbsp;H i c k 1 i n g, Ann. of Bot., XXI, p. 369, PI. XXXII-XXXIII. 4 textfigs.

1870. Williamson, Mem. Proc. Lit. Phil. Soc. Manch.. (3) IV, p. 248, PI. VIMX.
True fructification of Calamités.

1887. Williamson, On the organization, XIV, p. 47, PI. 8-11.
Calamités pedunculatus Williamson and Scott (non Williamson) (Diagn. in: Weiss 1884).

1894. Williamson and Scott, Further observations I p 916
DISTRIBUTION. - Hor. - Finefrau-Nebenbank.

England: Oldham. Strinesdale.
DUTCH MATERIAL. — Slides 60/0/2-3, 98/5/1. 98/6/1.
EXTENSIVE DESCRIPTION. - See above: hickling 1907.

DESCRIPTION. - The preservation of the two Dutch specimens is so poor that hardly any cells
can be recognized. Nevertheless there is no doubt but both specimens belong to this species

SPECIMEN I. Shdes 98/5/1 and 98/6/1. Fig. 109. - Only the sclerosed tissue surrounding the
vascular bundles, parts of the sclerenchyma of the bracts, a few traces of the subepidermal sclerenchyma
and the tips of some of the bracts (not shown in the photo) have been preserved. The sixteen protoxylem
canals, arranged in pairs, are very clearly shown. The structure of the vascular bundles is .not preserved

SPECIMEN IL Slides 60/0/2 and 60/0/3. Fig. 108. - Slide 60/0/2 contains only the tips of some of
the bracts. Shde 60/0/3 is. more complete. In the centre the sclerosed tissue surrounding the vascular bundles is
seen. As this ring has 8 protuberances, there must have been 16 protoxylem canals, but these have not been
preserved. Traces of the sub-epidermal sclerenchyma are present. The structure-less mass of spores is divided
by thin black hnes: the sporangia walls, and the sporangiophores are represented by black dots. On the outside

some of the bracts are seen. The number of these appendages appears to have been equal to that of the sporan-
giophores, i. e. sixteen.

It is very curious that the sporangiophores alternate with the bracts! This is not a
peculiarity of this slide only, but it is also clearly shown in the textfigures of Hickling\'S memoir (1907) and
in fig. 27 of SCOTT (1920). It is quite the reverse of the generally accepted opinion that the sporangiophores
spring from the axils of the bracts. I have not been able to find a satisfactory explanation

1909.nbsp;P.Bertrand,Zygopterid..p. HO, 208. textfigs 20-21, PI. XVI, figs 111-112.

1910.nbsp;Seward, Fossil Plants, II. p. 462, fig. 308B.
1920. Scott, Studies, 3d. Ed., I, p. 320, fig. 143.

1925.nbsp;Leclercq, Mém. in 4quot; de la Soc. Géol. de Belg., VI. p. 51, Pl. XXXV, fig. 1, XXXVI,
fig. 3.

1927.nbsp;Koopmans, Jaarverslag 1926, p. 50.
1927. Hirmer. Handbuch, I, p. 506, figs 607-610.

1872. Binney. Mem. Proc. Lit. Phil. Soc. Manch., XII, p. 99.
1872. Williamson, Proc. Roy. Soc. London, XX (136), p. 436.
1889. Williamson, On the organization etc., XV. p. 159, fig. 6.
Rachiopteris Lacattei [Binney (non Renault)] Williamson.

1886.nbsp;Felix, Abh. Geol. Spezialk. Preussen. Vn, 3, p. 10, Taf. L fig. 1.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

England: Deighton, Dulesgate, Halifax, Oldham, Shore, Stalybridge.
Hor. - Katharina.

Loc - Germany: Vollmond, Maria.
DUTCH MATERIAL. - Slides 5/1/1-2. 5/3/1-3. 5/4/1-2. 28/8/3-4. 28/9/2. 68/0/1-3. 81/0/1. 102/3/1-3,

DESCRIPTION. — Petioles of this species are fairly common. In outhne they are elliptical.
XYLEM. — The xylem (figs 113. 114, 123) has the well-known form of a double anchor. The
middle band consists of large reticulate tracheides and is somewhat swollen in the centre. At both ends two
club-shaped arms are inserted, which are thinnest, where they join the middle bar of xylem and become broader
near their free ends. The arms consist in the main of large tracheides, but on the outside there are one or
two rows of smaller elements, which, however, are not separated from the larger ones by parenchyma, as is
the case in Ankyropteris. The protoxylem is represented by a group of small tracheides on the outside of each

PINNA-TRACES. — These branch off in pairs from the protoxylems, alternately to the left and to the

right. The two traces from each pair soon unite to the quot;pinna-barquot;, but separate again when, on its outgoing
course, this pinna-bar reaches the cortex. In the cortex each trace is divided into two parts, viz. the leaf-trace
and the much smaller aphlebia-trace (fig. 113).
PHLOEM. — This is not preserved.

CORTEX. _The cortex consists of two zones, an inner zone of fairly large cells and an outer zone

of very small sclerosed ones. They are arranged in vertical rows and separated by horizontal walls. Those

on the inside are about as high as they are broad, but their length increases as their diameter decreases, so that
those on the outside may be ten times as long as those on the inside.

VARIATIONS. — Several slight variations have been observed. Sometimes the middle bar of the xylem
is quite straight; sometimes the arms are more slender than those of the type-specimen, with which the specimen
from coal-ball 28, fig. 113, quite agrees; sometimes the insertion of the arms seems to be different. Prof. PAUL
Bertrand who was so kind as to examine my slides, quite shared my opinion that as yet it is better to attach
no specific value to these minor variations. I have examined at Liège the slides, which MiSS LECLERCQ
(1925) ascribes to Etapteris Lacattei, but at present I regard this specimen also as one of these variations,
though I allow the possibility that it may belong to some species not yet described. Perhaps they are not varia-
tions at all, but only differences depending on the distance from the base of the petiole (comp. figs 113-114, 123).

1925.nbsp;Leclercq, Mém. in 4« de la Soc. Géol. de Belg., VI, p. 53, Pl. XXXVIII, fig 5, Pl.
XXXIX, fig. 6.

1927.nbsp;Hirmer, Handbuch, I, p. 522, figs 637-639.
Ankyropteris bibractensis (Renault) P. Bertrand var. westphaliensis P. Bertrand.

1909.nbsp;P. Bertrand, Zygopterid., p. 71, 219, figs 60-65, 68-77, textfigs 9-11, 23b, 24.

1910.nbsp;Seward, Fossil Plants, II, p. 454, figs 312C, 313.
Rachiopteris bibractensis Williamson (non Renault).

1874. Williamson, On the organization etc., VI, p. 697, figs 49-50.
Zygopteris bibractensis [Williamson (non Renault)] Scott.
1900. Scott, Studies, p. 286, fig. 99.
1907. T a n s 1 e y, New Phyt., VI, p. 60, fig. 9.
1909. Scott, Studies, 2d Ed., I, p. 316, fig. 118.
1909. Lotsy, Bot. Stammesgesch., II, figs 393/7, 395/2.
Ankyropteris bibractensis [Williamson (non Renault)] P. Bertrand.

1907. P. Bertrand, C. R. Acad. Sci. Paris, CXLIV, p. 1304.
Rachiopteris irregularis Williamson.

1889. Williamjson, On the organization etc., XV, p. 206, fig. 28 (In the explanation of the
plates: Rachiopteris inaequalis).
. ,, DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale mijn.
Germany: Rheinpreussen.
\'nbsp;Belgium: Bouxharmont.

England: Deighton, Halifax, Huddersfield, Oldham, Shore, Stalybridge.
DUTCH MATERIAL. — Slides 4/5/1-2.

DESCRIPTION. — Only one small petiole of this species, was found (fig. 115). It resembles very
closely the petiole figured by bertrand (1909), figs 64-65.

XYLEM. — The quot;apolarquot;, the middle band, which is slightly curved, is in the centre 3-4, at the extre-

mities 2 cells wide, and about 10 cells long. The quot;antennaequot;, the lateral portions, on the concave side are one
cell wide and 7 small, resp. 3 large cells long, those on the convex side one or two cells wide and about 10
cells long. The tracheides of the antennae are smaller than those of the apolar. On the. outer side of the
antennae lies a band of small xylem elements. The parenchyma which separated this band from the antennae
has disappeared, so that an open loop remains in places.

PINNA-TRACES. — No pinna-traces are present
PHLOEM. — The phloem has entirely disappeared.

CORTEX. _The cortex is wel preserved, the inner consisting of fairly big cells, and the outer of very

■ epidermis. — The epidermis is not recognizable.
SPINES. — Externally the petiole is studded with stout spineè.

1909.nbsp;P. B e r t r a n d. Zygopterid., p. 15, 223. PI. I. fig. 1; PL II. figs 8-13, PI. III-VII, textfigs 1-8.
1909. Scott, Studies, 2d Ed., I, p. 336, figs 126-128.

1925.nbsp;Leclercq. Mém. in 4quot; de la Soc. Géol. de Belg., VI, p. 53. PI. XXXIX, fig. 7. PI. XL, fig. 8.

1927.nbsp;K o o p m a n s, Jaarverslag 1926, p. 50.
1927. Hirmer. Handbuch, I, p. 489. figs 578-585.

1874. Williamson, On the organization etc., VI, p. 685, figs 20-27.
1885. Felix, Bericht naturforsch. Ges. Leipzig, p. 10.

1886 Felix. Abh. Geol. Spezialk. Preussen. VII. 3. p. 10. Taf. I. fig. 1.nbsp;^ .1

England: Dulesgate, Halifax. Oldham, Shore. Stalybridge, Strinesdale.
Hor. — Katharina.
Loc. - Germany: Vollmond.

DUTCH MATERIAL.-Slides 17/1/2. 17/2/1, 28/8/1-2. 91/0/1-2, 139/1/1-3, 139/2/1. 149/0/2-3.

DESCRIPTION. — The specimens consist of fragments of petioles. The outline of every fragment is
almost cylindrical.

XYLEM. — The xylem of a primary rachis ( figs 116-117) consists of four masses of pitted tracheides.
which may be compared to the four arms of Etapteris without the connecting middle bar. Each of these arms has\'
a protoxylem group on its lateral angle. bertrand (1909) observed that the protoxylem has sunk a little below
the surface of the wood. This could not be recognized with certainty in the Dutch slides. In the primary rachis
the four xylem-arms are separated by a thin-walled tissue, which, according to bertrand. belongs to the
phloem. In secondary rachides and those of higher order they have grown together and fom one mass of
tracheides with four diverging angles.

PHLOEM. — The phloem, which is not usually preserved, fills up the bays between the xylem-arms,
so that the outline of the stele is approximately square. About seven large elements can be recognized in thé
axial plane of symmetry in each bay of the figured specimen (fig. 116), forming a triangle. In the tangential
plane no more than three or four are seen, which lie in one row parallel to the xylem-surface. Sieve-plates could
not be recognized. According to BeRTRAND (1909) the thin-walled tissue just described connecting the arms
of the xylem also belongs to the phloem.

PINNA-TRACE. — The pinnae — if it is permissable to use this term, as Stauropteris has not got
pinnae sensu stricto — branch off in pairs, alternately to the left and to the right. Each strand repeats chiefly
the structure of the main bundle. In rachides of tertiary and higher order instead of four only three proto.xylem
groups may be present.

CORTEX. — The cortex, as far as it is preserved, consists of a fairly uniform sclerosed tissue. The outer
layers and the epidermis have been lost.

1924. P o s t h u m u s, Zittingsverslagen Kon. Akad. Wetensch. Amsterd., XXXIII p 883 (Proc
xxvn, p. 836).

1927. Hirmer. Handbuch, I, p. 533. (Fig. 651 is not B. tridentata, but B. forensis Renault!)
Rachiopteris tridentata Fehx.

1886.nbsp;Felix, Abh. Geol. Spez. Karte Preussen, VII, 3, p. 12, Taf. L fig. 2.
Rachiopteris hirsuta Williamson.

19H. P e 1 O u r d e, Paléontol. Végét., p. 276, fig. 69.
1920. Scott, Studies, 3d. Ed., I, p. 339, figs 149, 151.
1926. Posthumus, Fossihum Catalogus, Plantae, 12, p. 24.
Rachiopteris ramosa Williamson.

1891. Williamson, On the organization etc., XVIII, p. 261, figs 19-28.
1894. Williamson. Index, III, p. 71.
Botrijopteris ramosa (Williamson) Scott.

1900. Scott. Studies, p. 291.
1908. Scott, Studies, 2d Ed.. I. p. 326.
1910. Seward. Fossil Plants, II, p. 440, fig. 306.
1914. Pelourde, Paléontol, végét., p. 277.
1920. Scott. Studies. 3d Ed., I, p. 339, fig. 150.

1925.nbsp;Leclercq, Mém. in 4« de la Soc. Géol. de Belg., VI, p. 57, PI. XLII-XLV, figs 1-7.

DESCRIPTION. — In many sections, petioles of Botryopteris are present. Unfortunately not a single
stem has been found. Identification with either Botryopteris ramosa or Botryopteris hirsata has. therefore, been
impossible. I have thought it best to identify them all with the neutral collective species Botryopteris tridentata
Felix, as a perusal of the literature and of several collections of slides has taught me that as yet it is impos-
sible to distinguish with certainty the petioles of B. hirsuta from those of B. ramosa. Figures 110-112 show some
of the forms which have been found in the Dutch material.

XYLEM. — The xylem consists of an elliptical mass of tracheides. which has generally three, sometimes
only one or two. prominent protoxylem-points. directed towards the upper face of the petiole.
PHLOEM. — The phloem is not preserved.

CORTEX._The cortex consists of a small-celled tissue in which no differentiation could be recognized.

On the upper surface it is usually somewhat concave. Hairs or spines have not been observed.

1877. Williamson. On the organization. IX, p. 350, fig. 79.
Rachiopteris rotiindata Felix.

1886.nbsp;Felix, Abb. Geol. Spez. Karte Preussen, VII, 3, p. 15, Taf. 3, fig. 2.
Anachoropteris rotiindata Scott (non Corda).

1920. Scott, Studies, 3d Ed., I, p. 352, fig. 158.
1927. Koopmans, Jaarverslag 1926, p. 50.
Anachoropteris piilchra Hirmer (non Corda).

1927. Hirmer, Handbuch, I, p. 540, fig. 660.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale mijn.
Germany: Rheinpreussen.
England: Bacup, Oldham, Shore.
Hor. - Katharina.
Loc. - Germany: Maria, Vollmond.

DUTCH MATERIAL. — Slides 38/1/1-3, 98/6/1. 102/3/2-3, 102/4/1-3, 130/0/1, 148/0/1, 148/2/1.

DESCRIPTION. — Only transverse sections of the petiole are present. Their outline is an ellipse with
a slight concavity on the upper side (figs 133-134). Its diameter is usually about 3.5 X L5 mm.

XYLEM. — The vascular bundle is extremely incurved, but not spirally involved. The biggest trachei-
des are on the incurved ends, which are only one or two cells wide. No pits have been observed in the walls. The
protoxylem, situated on the left and right upper corners, is badly preserved. The space enclosed by the curva-
ture of the bundle is occupied by a black mass, possibly of sclerenchyma, of equally complex form: a T with
rounded edges.

CORTEX. — The cortex is of the usual type: an inner cortex of fairly large cells, which diminish gra-
dually towards the outside, and an outer cortex of very small, sclerosed cells.

NOMENCLATURE. — CORDA described two species of the genus Anachoropteris, A. pulchra and A.
rotundata, both from the Coal-measures of Radnitz (CORDA 1845). An extensive monograph on A. pti/c/jra
was published by KUBART (1916). Since CORDA\'S paper nothing has been pubhshed on A. rotundata. Figs
135 and 136 are reproductions of the original figures of CORDA, The only drawing of an English specimen
of this genus was given by WILLIAMSON (1877), who does not describe it, but only remarks that he can detect
no difference between this Oldham specimen and CORDA\'S A.rotundata. Having read CORDA\'S explanation of
the plate wrongly, WILLIAMSON calls it Rachiopteris gleiche — Rachiopteris, because he calls all petioles
Rachiopteris, and gleiche, in stead of gleichenioides, the specific name of Chorionepteris gleichenioides — imagi-
ning that CORDA had named his specimen: Chorionepteris gleiche. I have shown several botanists CoRDA\'S fi-
gure, asking them what name belonged to this rachis: it is very curious that all read Chorionepteris gleiche,
which proves that WILLIAMSON\'S error is very easily made. Westfalian specimens were figured by FeLIX(1886)
and by SCOTT (1920). FELIX gives a short description of his specimen, corrects the error of WILLIAMSON
and identifies them as Rachiopteris rotundata. ScOTT uses the name Anachoropteris rotundata (= A. pulchra)
according toBERTRAND (1909) and toKUBART (1916). who think the two species of CORDA identical. In my
opinion there is no doubt but the English, Westfalian, and Dutch specimens represent one species. Whether
the specimens of CORDA belong to one species or to two, I cannot say, as I have not seen the original slides.
But I am convinced that the ^Vest-European specimens are not to be identified with either of CORDA S species.
The vascular bundle of A. pulchra, as shown in CORDA\'S drawing and in KubART\'S beautiful photos, is always
spirally involved, that of our specimens is only incurved. Thus it is in A. rotundata. But the
outline of our specimens is quite different from A. rotundata. We need only compare figs 133-134 and 136
to demonstrate the difference more adequately than can be done with words. The oudine of all West-European
specimens which I have seen is a horizontal ellipse with a concavity on the upper side, that of CORDA\'S speci-
men a vertical oval without any concavity.

I, therefore, propose to recognize the West-European specimens as a separate species and to call it
Anachoropteris Williamsoni in honour of the first author who has mentioned it.

DUTCH MATERIAL. — Slides 4/2/1, 29/3/1-2, 40/0/1, 40/3/2, 85/0/3, ll3/l/2bis, 152/1/1.

DESCRIPTION. — In the above-mentioned slides are found sporangia, most of them empty, which must
belong to some member of the Inversicatenales (fig. 55). As they are always isolated, specific, and even generic
identification is impossible. They are of a roundish shape and the wall consists of one layer of small cells, with on
one side a broad band of enlarged cells acting as an annulus.

1925.nbsp;Leclercq, Mém. in 4quot; de la Soc. Géol. de Belg., VI, p. 69, PI. IX, fig. 13.
1927. Koopmans, Jaarverslag 1926, p. 50.

1866. Binney, Mem. Proc. Lit. Phil. Soc. Manch., V, p. 113.
Dictyoxylon oldhamium (Binney) Williamson.

1869. Williamson, Monthly Mier. Journ., II, p. 66.
Lyginodendron oldhamium (Binney) Williamson.

1873.nbsp;Williamson, On the organization etc., IV, p. 404, figs 1-29, 48.
1887. Solms-Laubach, Einleitung, p. 368, fig. 49.

1890. Williamson, On the organization etc., XVII, p. 89, figs 1-13.
1893. Williamson, Index, III, p. 58.

1896. Williamson and Scott, Further observations. III, p. 705, PI. XVIII-XXV.
1896. Felix, Földtani Közlöny, XXVI, p. 176.
1900. Scott, Studies, p. 308, figs 102-113.

1910.nbsp;Coulter and Chamberlain, Gymnosperms, p. 13, figs 11-13.
1913. W e i s s, F. E., Mem. Proc. Lit. Phil. Soc. Manch., LVII, 3, p. 1, 1 PL
1913. Brenchley, Journ. Linn. Soc., XLI, p. 349.

1921. Potonié-Gothan, Palaeobot., p. 126, figs 112-114.
On the petioles of Lyginopteris see also:
Edraxylon Williamson.

1874.nbsp;Williamson, On the organization etc., VI, p. 679, figs 1-14, 16.
1890. Williamson, On the organization etc., XVII, p. 89, figs 1-13.

1887.nbsp;Williamson, On the organization etc., XIII, p. 294, figs 20-37.
1895. Hick, Mem. Proc. Lit. Phil. Soc. Manch., (4) IX, p. 109, PI. II.

DUTCH MATERIAL. — Very common. At least 30 specimens.
EXTENSIVE DESCRIPTION. — See above: WILLIAMSON and ScOTT 1896.

DESCRIPTION. — Lyginopteris oldhamia is one of the commonest fossils in the Dutch material.
Several stems are preserved with great beauty (fig. 120).

MEDULLA. — The medulla consists of a parenchyma, in which sclerotic nests are embedded.

XYLEM. — At the periphery of the pith there are several distinct strands of primary xylem beyond which
there is a broad zone of secondary wood, the elements of which are arranged with great regularity in radial
rows. This secondary wood is split up by numerous medullary rays, which in tangential section have a muriform
outline. The pointed tracheides of both primary and secondary wood are pitted.

PHLOEM. — Though the soft tissues on the outer side of the wood are very well preserved in some of
the specimens, no phloem-elements could be recognized as such with certainty. The phloem-rays are clearly shown.

PERICYCLE. — The phloem-zone is surrounded by a ring of thin-walled tissue, which it is best to regard
as a pericycle. Embedded in this are groups of sclerotic cells similar to those which are conspicuous in the pith.

PERIDERM. — As a general rule at the exterior of the pericycle there is a layer of periderm consisting
of radially arranged elements. This periderm curves outwards opposite the leaf-traces, following their outer
surface.

CORTEX. — The inner cortex consists of large-celled collenchyma, among which sac-like cells are scat-
tered in some specimens. It is best preserved in those stems, in which the periderm is not yet present or has
been only slightly developed. The thickening at the angles, where the cells meet, is\' very characteristic. The
outer cortex is made up of the well-known alternating, radial bands of sclerotic fibres and parenchyma, forming

the Dictyoxylon-cortex. Beyond the sclerotic zone there are a few more layers of parenchyma, more or less
imperfectly preserved.

LEAF-TRACE. — With regard to the structure and the course of the leaf-traces I should hke to refer
to the very extensive description given by ScOTT (Studies, II, 1923, p. 28-33).

ROOTS. — Associated, and even connected, with the stems are found numerous roots of the well-
known type of Kaloxylon Hooked.

LEAVES. — Petioles (Rachiopteris aspera Will.) and leaves are even more common than the stems
themselves.

STRUCTURAL ANOMALIES. - Fig. 120 represents a stem of Lygino*pteris oldhamia, which shows
very clearly the anomaly described by WILLIAMSON and ScOTT (1895, p. 722), the appearance of a secondary
meristem, at the outer border of the pith, acting as a regular cambium and producing medullary wood and bast
with inverted orientation. The tertiary tracheides are arranged in regular rows and constitute a very conspi-
cuous feature of this slide.

England: Bacup, Deighton, Dulesgate, Halifax, Huddersfield. Oldham,
Shore, Stalybridge, Strinesdale.
DUTGH MATERIAL. — Slides 0/0/6, 3/2/1, 22/2/1, 29/3/2, 107/0/1, 108/0/1. 111/0/1, 132/0/4,

DESCRIPTION. _ Figure 128 shows the best longitudinal section procured of Lagenostoma ovoides.

The lower part of the sporangium, where it had been inserted, has been lost. No traces of the cupule have been
found, either in this or any other slide. The orifice of the sporangium, the pollenchamber with its central co-
lumn, and the megaspore membrane are very clearly shown. Figure 127 shows a somewhat oblique section
through another specimen.

1904. Benson, Ann. of Bot., XVIII. p. 161, PL XI, 1 textfig.
1907. Scott, Progr. Rei Bot., I, p. 201.
1909. Scott, Studies, 2d Ed., ii, p. 399.
1909. Lotsy, Bot. Stammesgesch., II, p. 717.
1917. Seward, Fossil Plants, III, p. 54, fig. 493E.
1923. Scott, Studies, 3d Ed., ii, p. 78.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale mijn.
England: Oldham, Shore.
DUTCH MATERIAL. — Slides 0/0/3, 40/0/3-4.
EXTENSIVE DESCRIPTION. — See above: BENSON 1904.

DESCRIPTION. — In several slides structures are found probably representing parts of synangia. I am
not quite sure that they can be identified with Telangium Scotti Benson, but think it best to regard them as
belonging to this species until better preserved specimens are found. Figs 123-125 give a good idea of the form
and structure of these remains.

1876. W i 11 i a m s o n. Rep. 45th meeting (Bristol) Brit. Ass., p. 159.
1909. Oliver, Ann. of Bot., XXIII, p. 73, PI. V-VII, 10 textfigs.

1910.nbsp;Coulter and Chamberlain, Gymnosperms, p. 34, figs 35-39.
1910. Gordon, Proc. Cambr. Phil. Soc., V, 5, p. 395.

1917. Seward, Fossil Plants, III, p. 309, figs 493C-D, 4941.
1923. Scott, Studies, 3d Ed., II, p. 84, fig. 43.
1927. Koopmans, Jaarverslag 1926, p. 50.

1877. Williamson, On the organization etc., VIII, p. 241, figs 77-79.
1897. But ter worth. Mem. Proc. Lit. Phil. Soc. Manch., XLI, 9. p. I. 1 P]

1883. Williamson, On the organization etc., XII. p. 469, fig. 27. (In the index to the plates
called: Sporocarpon anomalum.)
DISTRIBUTION. - Hor. - Finefrau-Nebenbank.

England: Bacup. Dulesgate. Hahfax. Oldham, Shore
DUTCH MATERIAL. —Slide 76(013.

DESCRIPTION. - Though the preservation is bad, the only slide available is striking enough to permit
the identification of this seed. It is cut transversely through the pollenchamber (fig. 126) at the same height
as textfigure 2C of OLIVER (1909). which is reproduced by SCOTT (1923) in figure 43C. In the centre
a black ellipse represents the apical papilla of the megaspore, which protrudes into the pollenchamber Thé
pollenchamber-wall is represented by a thin, black line, on the outer side of which are seen the ten tentacles
which are mvested by the very conspicuous, long, club-shaped hairs covering the summits of the ridges on thé
body of the seed and the outside of the tentacles. This investment is a very striking feature of Physostoma
making even the smallest fragments easy of identification.

1903. Arber, E. A. N., Ann. of Bot., XVII, p. 425, PI. XX.
1907. Scott, Progr. Rei Bot., I, p. 203, figs 35-37.

1910.nbsp;Coulter and Chamberlain. Gymnosperms. p. 18. fig. 15.
1909. Lotsy. Bot. Stammesgesch.. II. p. 719, fig. 512.

1914. Salisbury, Ann. of Bot.. XXVIII. p. 76.
1917. Seward, Fossil Plants, III, p. 90, fig. 416 A-C.
1921. Potonié-Gothan, Palaeobotanik, p. 135.

1924.nbsp;Scott, Extinct Plants, p. 127, fig. 39.
1927. Koopmans. Jaarverslag 1926, p. 50.

1910. H olden. New Phyt., IX, p. 253, figs 17-18.
^quot;giospermophyton americanum Hoskins.

1923. H o s k i n s. The Bot. Gaz., LXXV, p. 390, PI. XVII, figs 8-13, textfigs 2-7.

DUTCH MATERIAL. — Slides 98/2/1-6. 98/3/1-2. 98/4/1, 98/5/1. 98/6/1, 127/4/4-5.

Myeloxylon-. 17/1/1-2. 17/2/1.91/0/1-2. 102/2/1-3, 102/3/1-2. 149/0/3. 150/0/1-2.
mil 12-3.

DESCRIPTION. _ Coal-ball 127 contains one small specimen of which only the wood is preserved.

Coal-ball 98 contains 4 specimens. One of these is fairly big, but is not quite complete, part of one of the steles
being missing (fig. 118). The other three specimens are small (fig. 121). It is not impossible that all four belong
to one branching stem, but I have not been able to find conclusive evidence. Only the xylem and the periderm
are well preserved, all the soft tissues having been destroyed.

XYLEM. — All transverse sections show three distinctly separate steles. The whole interior of each
stele (fig. 119) is occupied by a mass of tracheides forming confluent groups. These groups were probably
interspersed with thin-walled conjunctive parenchyma, which is not preserved. A zone of secondary wood of
variable thickness surrounds the primary xylem. and is at once distinguished from the primary wood by the
radial sedation of its elements. The radial series of tracheides are as a rule more numerous than the medullary
rays; usually from two to four series of tracheides intervene between two rays.

PERIDERM. — The development of an internal periderm is a very striking feature in all specimens. It
forms a continuous, though very irregular, zone encircling the stem a little within the bases of the leaves. The
regular, radial arrangement of the cells at once characterizes this zone as a secondary formation. It usually
attains a thickness of 8 to 10 cells (figs 119 and 121).

LEAF-BASES. — The leaf-bases are poorly preserved. As far as can be seen, they have the typical
^yeloxylon structure. Of the hypoderma only traces are preserved; enough, however, to recognize the quot;Spar-
ganumquot; cortex. The inner parenchyma is traversed by numerous gum-canals and by collateral vascular bundles.
Isolated petioles (Myeloxylon) are fairly abundant. Fig. 122 shows a very well preserved specimen.

ROOTS._Numerous roots have been found associated with the stems. They have the usual triarch

DESCRIPTION. — Coal-ball 128 contains only the xylem of a Mesoxylon: coal-ball 158 contains a com-
plete specimen, which, however, is very poorly preserved. Nevertheless I think that both must be ascribed to
Mesoxylon multirame. My description will be based on the specimen from coal-ball 161, which is better pre-
served and is fairly complete.

MEDULLA. — The pith, which is badly preserved, seems to be of the ordinary discoid type. Figs 130
and 129 represent respectively a section through one of these discs and a section between two of them. The
diameter of the medulla is about 15 X 20 mm.

XYLEM. — The primary wood cannot be recognized, but the secondary wood, about 3 mm thick, is
well preserved. The tracheides are arranged in radial rows of about 100 cells. No pits can be observed. The
medullary rays are uniseriate, 1-12 cells in height. No wood-parenchyma is present.

PHLOEM. — The phloem is about 0,6 mm thick. It consists of some 15 rows of cells, which are
distinctly different in size. Whether the three kinds of cells described by SCOTT (1918, p. 450) are present
cannot be decided with certainty.

PERICYCLE. — The pericycle (average width about 1 m.m.) is to be recognized at once from the phloem
by the irregular arrangement and the greater size of the cells. The matrix is formed of small-celled parenchyma,
but embedded in this are very numerous and peculiar sacs, of large size, sometimes filled with black material,

PERIDERM. — The periderm, formed at the outside of the pericycle, consists of 5-15 small, tangen-
tially elongated cells.

CORTEX. — The cortex is a broad zone of an irregular parenchyma. The inner part contains a few

sac-like cells resembling those of the pericycle. On the outer side the greater part of this zone is\' occupied by a
mechanical Dictyoxylon tissue. The fibrous bands of this Dictyoxylon cortex often form a network.

LEAF-TRACE. — The structure and behaviour of the leaf-traces closely agree with the detailed des-
cription given by ScOTT (1918, p. 439 and 446). After reaching the pith the twin bundles of the trace
remain distinct for several internodes and never definitely fuse before they are merged into the woody zone.
The trace divides into eight bundles in the cortex. The centropetal xylem persists about as long as the two
strands remain distinct (figs 131-132). Textfigure 3 shows diagrammatically the relative position of 18 leaf-
traces in slides 161/0/5-6. The phyllotaxis is of the main series.

LEAVES. — Both in coal-ball 158 and 161 leaves are found associated with the stems. They are of
the usual Cordaitean type (See: Gordaites Felicis, figs 62-65).

1912. Benson, Ann. of Bot., XXVL p. 201, PI. XXII, 1 textfig.
1917. Seward, Fossil Plants, III, p. 227, fig. 465.
1927. Koopmans, Jaarverslag 1926, p. 50.
1927. Leclercq, Ann. Soc. Géol. de Belg., LI. 2, p. 56, fig. 1.
Mesoxylon Felicis (Benson) Scott.

1886. Felix, Abh. Geol. Spez. Karte Preussen, VII, 3, p. 63, Taf. Ill, fig. 5.
1912. Benson, Ann. of Bot., XXVI, p. 205.
Cordaites robustus Felix.

1886. Felix, Abh. Geol. Spez. Karte Preussen, VII, 3, p. 64, Taf. Ill, fig. 1.
1912. Benson, Ann. of Bot., XXVI, p. 205.
1917. Seward, Fossil Plants, III, p. 227.
Cordaites Wedekindi Felix.

1886. Felix, Abh. Geol. Spez. Karte Preussen, VII, 3, p. 61, Taf. Ill, fig. 4.
1912. Benson, Ann. of Bot., XXVI, p. 205.
1923. Scott, Studies, 3d Ed., II, p. 292.
Cordaites weristeri Leclercq.

1927. Leclercq, Ann. Soc. Géol. de Belg., LI, 2, p. 57, figs 1-2, 2-6bis.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

Loc. - Limburg: Domaniale mijn.
Germany: Rheinpreussen.
Belgium: Bouxharmont.
England: Dulesgate, Halifax, Shore.
Hor. - Katharina.
Loc. - Germany: Maria, Vollmond.
DUTCH MATERIAL. — Slides 92/0/1-2, 158/0/1-2, 161/0/1-4.

EXTENSIVE DESCRIPTION. — See above: Felix 1886, benson 1912. Leclercq 1927.
DESCRIPTION. — All the specimens of Cordaitean leaves in the Dutch material are poorly preserved.
They are of the general Cordaitean structure, with numerous parallel collateral bundles. Three types can be
distinguished:

a: Complete fibrous partitions, longitudinally disposed, alternating with the bundles. Each bundle is
surrounded by a well-developed sheath (Cordaites Wedekindi Felix) (fig. 64).

b: Complete fibrous partitions. No sheath. (Cordaites loculosus Felix) fig. 62-63).

c: No fibrous partitions. Sheath present. (Cordaites lyen\'sfen\'Leclercq) (fig. 65).

Dr. Benson (1912) has been able to show that the species of felix are probably part of the same leaf.
Although she has not definitely identified them with Cordaites Felicis Benson, the evidence points to their
identity with this species.

Dr. susanne Leclercq (1927) has recently given a description of some leaves, which she calls Corlt;iarYes
weristeri and which are probably identical with my third type. While it is possible that Cordaites weristeri
represents a distinct species, it is a very curious fact, that miss LeCLERCQ finds in the same slide a leaf of
Cordaites Felicis, Cordaitean leaves being vere rare in the Belgian material, and it is a still more curious coin-
cidence that Felix, Miss Benson, and myself, also find several forms together in the same ball. FelIX
finds associated C. Wedekindi and C. loculosus, miss benson forms resembling C. Wedekindi, C. loculosus,
and C. robustus, and I have forms resembling C. Wedekindi and C. weristeri, even in two coal-balls (158 and
161). As Cordaitean leaves are always rather rare, it seems highly improbable that in all these cases more
than one species is present, the more so, as r^^iss benson has shown her specimens to belong to one species.
Under the circumstances I am inclined to regard Cordaites weristeri Leclercq as a synonym of Cordaites Felicis
Benson and identify all my specimens with Cordaites Felicis Benson.

AFFINITIES. — In coal-ball 158 and 161 these leaves are closely associated with Mesoxylon multiramc
Scott and Maslen. Though as yet they have not been found in connection with this stem, it seems fairly certain
that they represent its foliage. In the absence of clear proof that they cannot belong to any other genus, e.g.
Cordaites, I do not think it advisable to call them Mesoxylon Felicis, as proposed bySCOTT (1923).

1872. Williamson, Proc. Roy. Soc. London, XX, p. 436.
1874, Williamson, On the organization etc., V, p. 67, figs 46-56.

1886.nbsp;Felix, Abh. Geol. Spez. Karte Preussen, VII, 3, p. 52, Taf. III, fig. 3.

1887.nbsp;Solms-Laubach, Palaeophytologie, p. 378.
1909. Scott, Studies, 2d Ed., II, p. 530, fig. 191.

1910,nbsp;Coulter and Chamberlain, Gymnosperms, p. 171, fig. 203.
1923. Scott, Studies. 3d Ed., II, p. 286, fig. 105.

1927, Leclercq, Ann. Soc. Géol. de Belg., LI, 2, p. 63, figs 7-8.
Dictyoxylon radicans Williamson.

1872. Williamson, Rep. Brit. Ass., 41st meeting (Edinb.), p. 111.
DISTRIBUTION. — Hor. - Finefrau-Nebenbank.

England: Dulesgate, Halifax, Oldham, Shore, Strinesdale.
Hor. - Katharina.
Loc. — Germany: Maria, Vollmond.
DUTCH MATERIAL. — Slides from coal-balls 4, 13. 25, 26, 38, 81, 85, 92, 95, 98, 110, 112, 126,

DESCRIPTION. — Though it is generally accepted that Amyelon represents the root of Mesoxylon

and Cordaites, I prefer to consider it as a distinct species, as it is not yet possible to identify it with the stem
to which it belongs. In the Dutch specimens only the xylem and the periderm are preserved.

XYLEM. — In the figured specimen (fig. 61) the centripetal primary wood is pentarch. Owing to con-
traction it is very clearly shown in this slide, but in the other specimens it is very difficult to distinguish the
primary from the secondary wood. The primary wood is usually triarch. The secondary zone is made up of
radially arranged tracheides. In some longitudinal sections Araucarioxylon-pits can be recognized.
PERIDERM. — The periderm consists of several layers of radially arranged elements.

All figured slides and slabs are in the collection of the „Geologisch Bureau voor het Nederlandsche Mijn-
gebiedquot; at Heerlen.

Pjg- 1. Slide 144/9/2. X 5. Transverse section showing the xylem, the outer cortex, and the leaf-bases. In several

leaf-bases the ligular pit, the vascular bundle, and the parichnos are clearly shown.
Pig. 2. Slide 144/13/2. X 5. Radial section through the leaf-bases. In the upper one the ligula is seen inside the

ligular pit and to the left of this the parichnos.
Fig. 3. Slide 144/13/6. X 5. Tangential section through the leaf-bases. This section has been cut so near to the
cortex that in several leaf-bases the hgular pit is not yet present and the parichnos has not yet branched
into two.

Fig. 4. Slide 144/9/10. X 5. Tangential section through the outer part of the leal-bases.

Fig. 10. Slide 144/8/6. X 2. Radial section through the xylem and the leaf-bases.

Fig. 11. Slide 144/8/10. X 50. Tangential section through the xylem, showing the bifurcating of the protoxylem-

ridges. Compare textfigure 2.
Fig. 12. About natural size. Block 1578 from the Wild collection at Manchester, showing the outer surface of

Lepidophloios laricinus.
Figures 13-26: Lepidophloios macrolepidotus Goldenberg.

Figs 13-22. Polished slabs from coal-ball 162. X 2. Heerlen coll. 753/A 1-2, 753/B 6, 15, 753/D 1-4.
Figs 13-15. Transverse sections of the leaf-bases at different levels.

Figs 16-20. Five consecutive tangential sections of the same leaf-bases from without inwards.
Fig. 21. Radial section through a leaf-base showing the course of the ligular pit.
Fig. 22. Radial section through a leaf-base showing the course of the parichnos.

Figs 23-26. Slides 8/1/5. 8/1/4. 8/1/3, 8/1/2 X 2. Four consecutive tangential sections of another specimen, sho-
wing the same leaf-bases at different levels, from within outwards.

Fig. 27. Slide 160/10/8. X 3. Transverse section through a very complete stem of moderate age.
Fig. 28. The xylem of fig. 27. magnified 25 times.

Fig. 29. Slide 160/7/1. X 3. Somewhat oblique section through the same stem. Compare WILLIAMSON, On the
organization, XI, fig. 9!

Fig. 30. Slide 13/3/4. X 3. Tangential section at the periphery of the leaf-bases. Observe the aerenchyma.

Fig. 31. Slide 160/10/7. X 3. Tangential section through the leaf-bases at a deeper level.

Fig. 32. Slide 160/10/5. X 3. Radial section through the leaf-bases, showing the course of the ligular pit.

Fig. 33. Sigillatia cf. elegans Brongniart. Slide 64/0/1. X 25. Transverse section, tnrough the xylem.

Figures 34-50: Lepidodendron obovatum Sternberg. All figures from polished slabs from coal-ball 167 and mag- ^

nified 2 times, except figure 48, which is about natural size. Heerlen coll.: 755/A 1-13, 755/B 1, 755/D 1, 3.
Figs 34-36. Thirteen consecutive transverse sections from below upwards through the same leaf-bases, showing
its outer surface and the position of the Hgular pit, the vascular bundle, and the parichnos at different
levels. Observe the aerenchyma in figs 37-38.
Fig. 47. Radial section through two leaf-bases.
Fig. 48. Outer surface of the block.

Figures 51-54, 56-60: Lepidodendron aculeaturn Sternberg. All figures from polished slabs from coal-ball 166 and

magnified 2 times. Heerlen coll.: 754/B 1-5, 754/C 4, 754/E 2, 5, 754/F 1.
Fig. 51. Radial section through a leaf-base, showing the parichnos and the ligular pit.

Figs 52-54. Tangendal sections through the leaf-bases, showing their structure at different levels. Observe the
aerenchyma in fig. 52.

Figs 56-60. Five consecutive transverse sections of the same leaf-bases from below upwards.
Fig. 55. Slide 152/1/1. X 30. Sporangia of some member of the Primoft7ices.

Fig. 61. Amyclon vadicans Will. Slide 13/2/2. X 10. Transverse section through a root of moderate age.

Fig. 66. Slide 28/1/3. X 7/3. Transverse section through a strobilus.
Fig. 67. Slide 28/2/3. X 7/3. Radial section through the same specimen.
Fig 68. Slide 131/0/3. X 3. Transverse section through a crushed specimen.

Fig. 69. Slide 40/4/1. X 25. Transverse section through an isolated axis showing beautifully the arrangement of
the sporophyll-traces.

Fig. 70. Slide 145/2/2. X 5. Transverse section through the top of a young strobilus, showing the sterile tissue
in the sporangia.

Fig. 71. Lepidostrobus cf. foliaceus Maslen. Slide 40/6/2. X 5. Nearly radial section.

Fig. 72. Stigmaria arachnoidea nov. spec. Slide 56/0/2. X 10. Two appendages. Compare fig. 92.

Fig. 73. Slide 40/2/6. X 10. Obliquely radial section. Note the downward curve of the vascular bundle of the
uppermost sporophyll.

Fig. 74. Slide 40/2/5. X 10. Tangential section. Observe the development of the wings of the sporophyll.
Fig. 75. Slide 40/3/2. X 10. Transverse section. Note that the xylem is nearly solid.

Pig. 76. Slide 96/1/2. X 10. Tangential section through a cluster of quot;seedsquot; in the mature condition.
Pig. 77. Slide 5/3/2. X 10. Tangential section through a seed in the naked condition.

Pig. 78. Slide 28/9/2. X 10. Tangential section through a small, mature, seed. Observe the very long quot;micropylequot;.
Pig. 79. Slide 63/0/2. X 5. Horizontal section through a mature seed.
Pig. 80. Slide 96/5/2. X 5. Tangential section through a mature seed.

Pig. 83. Slide 12/3/2. X 40/3. Tangential section of the xylem. Observe the regular arrangement of the appen-
dage-traces.

Pig. 84. Slide 54/0/3. X 20/3. Transverse section of xylem, cortex, and appendages of another specimen.
Pigures 85-86: Diploxylon 144.

Pig. 85. Slide 144/10/2. X 2. Transverse section of xylem and cortex. Observe the lamellae of the periderm.
Pig. 86. Shde 144/11/3. X 10. Transverse section of the xylem.

Pigures 87-88. Diploxylon 89. Slide 89/0/5. X 10. Transverse section of the xylem.

Pig. 89. Lepidodendvon obovatam Sternberg. Slide 167/0/1. X 10. Transverse section of the xylem.

Figures 90-91 bis: Lepidophloios macrolepidotiis Goldenberg.
Pig. 90. Slide 162/1/2. X 10. Transverse section of the xylem.

Pig. 91. Outer surface of a block from the English Coal-measures in the Heerlen collection, (no. 225). The

structure of the stem contained in this block is the same as that of my specimens.
Pig. 91 bis. Slide in the Heerlen collection (no. 225/1) cut. from the block of fig. 91, X 25. Transverse section
of the xylem, showing the corona.

Fig.nbsp;92. Stigmaria arachnoidea nov. spec. Slide 56/0/2. X 25. Compare fig. 72.

Pig.nbsp;96. Sigillaria c[. mamillaris Brongniart. Block 715 of the Heerlen collection. About natural size.

Pig.nbsp;97. Sphenophyllostachys Dawsoni (Will.) Seward. Slide 27/6/3. X 10. Obliquely radial section.

Figures 100-104. Sphenophyllum plurifoliatum Will, et Scott. Slides 27/0/9-27/0/5. X 25.

Fig.nbsp;105. Calamités communis Binney. Slide 28/3/4. X 5. Transverse section through a stem of moderate age.

Pig.nbsp;106. Calamostachys oldhamia Hick and Lomax. Slide 89/0/6. X 5. Radial section.

Pig.nbsp;107. Calamostachys Binneyana (Carr.) Schimp. Slide 28/7/2. X 10. Tangential section.

Fig. 108. Slide 60/0/3. X 10. Oblique section. Above the axis three, and to the right of it two, sporangiophores

are seen as black dots in the structureless mass of spores.
Fig. 109. Slide 98/5/1. X 10. Oblique section through the axis. Note the sixteen protoxylem-canals.

Figures 110-112: Botryopteris tridentata (Felix) Posthumus.
Pig. 110. Slide 28/8/3. X 40/3.

Fig. 113. Slide 28/8/4. X 10. Observe the outgoing leaflet-traces in the cortex and the much smaller aphlebia-
traces.

Fig. 115. Ankyropteris westphaliensis P. Bertrand. Slide 4/5/1. X 10. Note the spines on the cortex. To the left:
Megaspore of Lepidodendron or Bothrodendron.

Figures 116-117: Stauropteris oldhamia Binney.
Fig. 116. Slide 139/1/1. X 25.
Fig. 117. Slide 28/8/2. X 33.

Fig. 118. Slide 98/6/1. X 3. Transverse section through a nearly complete stem. The leaf-bases to the right are
not preserved.

Fig. 119. Shde 98/2/3. X 10. One of the steles of another shde of the same specimen. To the right a leaf-trace
is passing out.

Fig. 121. Slide 98/6/1. X 5. A small stem in which the three steles and the periderm are clearly shown.

Fig. 120. Lyginopteris oldhamia (Binney) Potonié. Slide 14/1/4. X 10. Above a root is seen passing out. Between
the xylem and the cortex several leaf-traces are seen. Observe the centripetal, secondary wood in the
medulla.

Fig. 122. Myeloxylon. Slide 150/0/2. X 7.
Figures 123-125: Telangium cf. Scotti Benson.

Fig. 123. Slide 102/3/2. X 10. Two empty synangia and a petiole of Etapteris cf. Scotti.
Fig. 124. Slide 0/0/3. X 10.

Fig. 126. Physostoma elegans Will. Slide 76/0/3. X 10 Transverse section through the top of a seed.

Fig. 129. Slide 161/0/6. X 3. Transverse section through the stem between two of the diaphragms.
Fig. 130. Slide 161/0/5. X 3. Transverse section immediately below that of fig. 129, through a diaphragm of
the medulla. Compare the development of the leaf-traces in both slides. Compare also textfigure 3 which
shows the same slides.

Figs 131-132. Slide 161/0/6. Leaf-traces at the periphery of the medulla showing the centripetal, primary wood.
Figures 133-134: Anachoropteris Williamsoni nom. nov.
Fig. 133. Slide 98/6/1. X 25.
Fig. 134. Slide 148/2/1. X 25.

Fig. 135. Anachoropteris pulchra cor da. X ?. (After Corda, reduced.)
Fig. 136. Anachoropteris rotundata Corda. X ?. (After Corda, reduced.)

Arber. Agnes, 1910, On the structure of the Palaeozoic seed Mitrospermum compressum (Will). Ann. of
Bot.. XXIV. p. 491-509. PI. XXXVII-XXXIX, 2 textfig.

—nbsp;1914, An anatomical study of the Palaeozoic cone-genus Lepidostrobus. Trans. Linn. Soc. London.

(2) Botany, VIII, p. 205-238, PI. XXI-XXVII, textfigs 1-4.
Arber, E. A. N., 1902, Notes on the Binney collection of Coal-measure plants III. The type-specimens of
Lyginodendron oldhamium (Binney). Proc. Cambr. Phil. Soc.. XI, p. 281.

—nbsp;1903, On the roots of Medullosa anglica. Ann. of Bot.. XVII, p. 425-433, PI. XX.

—nbsp;1907, Bibliography of literature on Palaeozoic fossil plants. Progressas Rei Botanicae. I, p. 218.
Arber, E. A. N. and H. H. Thomas, 1909, On the structure of Sigillaria scutellata Brongn. and other Eusi-

gillarian stems, in comparison with those of other Palaeozoic Lycopods. Phil. Trans. Roy.
Soc. London, b, cc, p. 133-166. pl.xiv-xvi.
Benson, M.. 1902, The fructification of Lyginodendron oldhamium. Ann. of Bot., xvi, p. 575-576, 1 textfig.

—nbsp;1904, Telangium Scotti, a new species of Telangium ( Calymmatotheca) showing structure. Ann.

—nbsp;1908-1, The sporangiophore — a unit of structure in the Pteridophyta. Neiv Phyt., VII, p 143-

—nbsp;1908-2, On the contents of the pollen-chamber of a specimen of Lagenostoma ovoides. Bot. Gaz.,

—nbsp;1912, Cordaites Felicis sp. nov., a Cordaitean leaf from the Lower Coal-measures of England.

—nbsp;1914, Recent advance in our knowledge of Sigillaria. Brit. Ass. Rep.. 1914, p. 584.

—nbsp;1918, Mazocarpon, or the structure of SigiHariostrobus. Ann. of Bot., XXXII, p. 569-589, PI.

Bertrand, C. Eg., 1891, Remarques sur le Lepidodendron Harcourtii de Witham. Trav. ct Mém. des Fac. de

—nbsp;1899, On the structure of the stem of a ribbed Sigillaria. Ann. of Bot., xiii, p. 607-609.
Bertrand, p.. 1909, Etudes sur la fronde des Zygopteridées. Lille, 1909, 286 p., avec atlas: xvi Pl.

—nbsp;\' 1911, Nouvelles remarques sur la fronde des Zygopteridées. Autun, 1911, p. 1-38, Pl. I-IV.
Binney. e. w., 1862, On some fossil plants, showing structure, from the Lower Coal-measures of Lancashire.

_ 1555^ p^ description of some fossil plants showing structure found in the Lower Coal-seams of

\' Lancashire and Yorkshire. Phil. Trans. Roy. Soc. London, CLV, p. 579-604, PI. XXX-
XXXV.

—nbsp;1868, Observations on the structure of fossil plants, found in the Carboniferous Strata. I. The

Bower. F. O.. 1908, The origin of a landflora. London, p. i-XI, 1-727, figs 1-361.

Brenchley, Winifred E., 1913, On branching specimens of Lyginodendron oldhamium Will. Journ. Linn.
Soc., Botany, XLI, p. 349.

BRONGNIART A.. 1839, Observations snr la structure interne du Sigillaria elegans comparée à celle des Lepi-
dodendron et des Stigmaria et à celle des végétaux vivants. Archives du Museum, l, p. 405-

BuTTERWORTH. j.. 1897, Some further investigation of fossil seeds of the genus Lagenostoma (Williamson)
from the Lower Coal-measures, Oldham. Mem. Proc. Lit. Phil. Soc. Manchester, XLL 9,

CARRUTHERS. W.. 1866, On the structure and affinities of Lepidodendron and Calamités. Trans. Bot. Soc.

Edinh., Vin, p. 495-507, PI. VIII-IX.
_ 1867 On the structure of the fruit of Calamités, journ. of Bot., V. p. 349-356, PI. LXX.
_ 1869-1, On the structure and affinities of Sigillaria and allied genera. Q. /. Geol. Soc., XXV. p.

_ 1869-2. On the structure of the stems of the arborescent Lycopodiaceae of the Coal-measures. L.

CASH. W., 1887. On the fossil fructifications of the Yorkshire Coal-measures. Proc. Yor/c^. Geo/. Po/yf. Soc..

IX, p. 435-458, PL XXII-XXIX.
cash. W. and J. lomax. 1890. On Lepidophloios and Lepidodendron. Proc. Yorks. Geol. Polyt. Soc., XI. p.

CHAMBERLAIN C. J.. 1910. See COULTER. ]. M. and C. J. CHAMBERLAIN. 1910
CORDA. A. J.. 1845. Beiträge zur Flora der Vorweh. Prag. VIII 128 pp.. PL I-LX.

COULTER. J. M. and C. J. CHAMBERLAIN. 1910, Morphology of Gymnosperms. Chicago, p. I-XI, 1-458. figs

DAWSON. J. W.. ISn\'^On the structure and affinities of Sigillaria. Calamités, and Calamodendron. Q. J. Geol.

Soc.. XXVII. p. 147-161. PL VII-X.
DELTENRE, H. 1926. Les Sigillaires des charbonnages de Mariemont. Mém. Inst. Géol. Univ. Louvain, HI.
p. 1-116, PL I-XXIII.

toix! J.: 1886, Untersuchungen über den inneren Bau westfälischer Carbon-Pflan.en, I. A,„s„ä,. .u. Geol.
Spezialkarte von Preussen, VII, 3. p. 1-73. Taf. I-VI.
_ 1896. Ibid, IL Földtani Közlöny, XXVI. p. 165-179, Taf. IV-V.
GORDON. W. T.. 1910, On a new species of Physostoma from the Lower Carboniferous rocks of Pettycur

(Fife). Proc. Cambr. Phil. Soc., XV. 5. p. 395.
gothan. w.. 1921. see: potoniê. 1921.

HICK. T.. 1891. On a new fossil plant from the Lower Coal-measures. Journ. Unn. Soc. Bot., XXIX. p. lUZ.
PL XVI-XVII.

1894.nbsp;On the primary structure of the stem of Calamités. Mem. Proc. Lit. Plnl. Soc. Manch., (4).

1895,nbsp;On Kaloxylon Hooked Will, and Lyginodendron oldhamium Will. Mem. Proc. Lü. Phü.

_ 1896, On Rachiopteris cylindrica Will. Mem. Proc. Lit. Phil. Soc. Manch., XLI, 16 p PL

HICK, T. and J. LOMAX. 1894, On a new sporiferous spike from the Lancashire Coal-measures. Mem. Proc.
Lit. Phil. Soc. Manch., (4), VIII. 8 p.. 4 figs.

Hickling, g., 1907, The anatomy of Palaeostachya vera. Ann. of Bat., XXI, p. 369-386, pi. XXXII-XXXIII,
textfigs 1-4.

—nbsp;1910, The anatomy of Calamostachys Binneyana Schimper. Mem. Proc. Lit. Phil. Soc. Manch.,

HiRMER, M.. 1927, Handbuch der Palâobotanik, i. München und Berlin, p. i-XVI, 1-708, figs 1-817.

Holden, H. S.,1910, Note on a wounded Myeloxylon. New Phyt.. IX, p. 253, figs 17-18 A, B.

Hoskins, j. HobART, 1923, A Paleozoic Angiosperm from an American coal-ball. The Bot. Gaz..Vo\\.LXXW.

p. 390-399, 7 textfigs, PI. XVII.
HovelaqUE, M., 1892, Recherches sur le Lepidodendron selaginoides Sternb. Mém. Soc. Linn. Normandie,

XVII, 1, p. 1-161, PI. I-VII.
JONGMANS, W., 1914, Equisetales. Fossilium catalogus, II, Plantae, editus a W. Jongmans, pars 3 et 4. (W.

KidstON, R.. 1893, On Lepidophloios and on the British species of that genus. Trans. Roy. Soc. Edinb.,

—nbsp;1905, On the internal structure of Sigillaria elegans of Brongniart\'s „Histoire des Végétaux fossi-

—nbsp;1907 Preliminary note on the internal structure of Sigillaria mamillaris Brongniart and Sigillaria

\' scutellata Brongniart. Proc. Roy. Soc. Edinb.. XXVII, 3, p. 203-206, figs 1^2.
Kisch, Mabel H., 1913. The physiological anatomy of the periderm of fossil Lycopodiales. Ann. of Bot.,

XXVII, p. 281-320, PL XXIV, 27 textfigs.
Koopmans. R. G.. 1927, Voorloopig verslag over het onderzoek der Dolomietknollen uit de Domaniale Mijn.

Geol. Bureau voor het Nederlandsche Mijngebied. Jaarverslag 1926, p. 50-51.
Kubart, B.. 1916, Bin Beitrag zur Kenntnis von Anachoropteris pulchra Corda. Denkschr. Kais. Acad. Wiss.

\' Wien, Math.^Naturw. Klasse, XCIII, p. 1-34, Pl. I-VII, 26 textfigs.
Leclercq. SuSANNE, 1925, Les coal-balls de la couche Bouxharmont des charbonnages de Wérister. Mém. in
4\' de la Soc. Géol. de Belgique, VI, p. 1-79, Pl. I-XLIX.

—nbsp;1927, Les végétaux a structure conservée du Houiller Belge, I. Feuilles et racines de Cordaitales

des coal-balls de la couche Bouxharmont. Ann. de la Soc. Géol. de Belgique, li, 2, p. B53-
B66, textfigs 1-2, Pl. I, figs 1-8.
Lomax. j., 1890. See cash, W. and j. lomax. 1890.

—nbsp;1902-1, On some features in relation to Lyginodendron oldhamium. Ann. of Bot., XVI, p. 601^602.
_ 1902-2, On the occurence of the nodular concretions (coal-balls) in the Lower Coal-measures.

Ann. of Bot., XVI, p. 603-604.
MasleN. a. J.. 1899, The structure of Lepidostrobus. Trans. Linn. Soc. London, 2, Bot., V, p. 357-377, PI.
XXXVI-XXXVIII.

—nbsp;1905, The relation of root to stem in Calamités. Ann. of Bot., XIX, p. 61-73, PI. I-II.

NOË. A. C.. 1923-1, A Palaeozoic Angiosperm. The Journal of Geology, XXXI, p. 344-347, 2 textfigs.

—nbsp;1925, Coal-balls here and abroad. Trans. Illin. State Acad., Science, XVII, p. 179-180.

Oliver. F.W.. 1903, On the identity of Sporocarpon ornatum Will, and Lagenostoma physoides Will. New
Phyt., II, p. 18-19.

—nbsp;1909. On Physostoma elegans Williamson, an archaic type of seed from the Palaeozoic rocks.

Ann. of Bot., XXIII, p. 73-116, PI. V-Vll, 10 textfigs.
OSBORNE. T. G. B.. 1909, The lateral roots of Amyelon radicans Will, and their Mycorhiza. Ann. of Bot.,
XXIII, p. 603.

posthumus. O.. 1926. Inversicatenales. Fossi/mm cafa/o^«s editus a W. Jongmans, II, Plantae, 12, p. 1-56.
(W. Junk, Berlin.)

potoniê. H.. 1893-1. Ueber ein Stammstück von Lepidophloios macrolepidotus Goldenberg (1862) mit erhaltener

Structur. Zeitschr. Deutsch. Geol. Ges., XLV. p. 330.
_ 1893-2. Anatomie der beiden Male auf dem unteren Wangenpaar und der beiden Seitennärb-
chen der Blattnarbe des Lepidodendreen-Blattpolsters. Ber. Deutsch. Bot. Ges., XI. p. 319-
326, Taf. XIV.

_ 1899 Lehrbuch der Pflanzenpalaeontologie. Berlin, p. I-VIII, 1-402, figs 1-355.

192l\', Lehrbuch der Palaeobotanik. Zweite Aufl., umgearb. von Prof. Dr. W. GOTHAN. Berhn, p.
I-IV, 1-537, figs 1-326.

PRANKERD, T. L.. 1912, On the structure of the Palaeozoic seed Lagenostoma ovoides Will. Linn. Soc. Journ.,

Bot., XL, p. 461-490, PI. XXII-XXIV, 3 textfigs.
REED FrEDDA Doris. 192 .. Flora of an Illinois coal-ball. The Bot. Gaz., LXXXI, 44, p. 460.
RENIER. A.. 1926. Sur lexistence de coal-balls dans le bassin houiller des Asturies. Compt. rend, séances Acad.

5c.. CLXXXn, p. 1290-1292.
salisbury. E. J.. 1913. Methods of palaeobotanical reconstruction. Ann. of Bot., XXVII. p. 273-279, 1 te^ .g.
_ 1914, On the structure and relationships of Trigonocarpus shorensis sp. nov. Ann. of Bot., AAVlll.
p. 39-80, PI. IV-V, 8 textfigs.
scott. D. H.. 1894. See: williamson. W. C. and D. H. scott. 1894.

—nbsp;1896, Ibid. 1896.nbsp;t ^u •
_ 1897 On the structure and affinities of fossil plants from the Palaeozoic rocks. I, On Chei-

\' rostrobus, a new type of fossil cone from the Lower Carboniferous Strata (Calciferous Sand-
stone Series). P/zf/. Trans. Roy. Soc. London, B, CLXXXIX, p. 1-34, PI. I-VL
_ 1899, On the structure etc.. III. On Medullosa anglica. Phil. Trans. Roy. Soc. London, B,

CXCI, p. 81-126, PL V-XIII.
_ 1900, Studies in fossil Botany. London, p. I-XIII, 1-533, figs 1-151.
_ 1900 On Lepidocarpon. Proc. Roy. Soc. London, LXVII, p. 306.

190l\' On the structure etc., IV, The seed-like fructification of Lepidocarpon. a genus of Lyco-
\' podiaceous cones from the Carboniferous formation. Phil. Trans. Roy. Soc. London, B.
CXCIV. p. 291-333, PL XXXVIII-XLIII.
_ 1902, The old wood and the new. New Phyt., I. p. 25.
_ 1903 Professor Bommer on Lepidocarpon. New Phyt., II, p. 19-22.

_ 1904-1. On the occurence of Sigillariopsis in the Lower Coal-measures of Britain. Ann. of Bot.,

_ 1904-2 Germinating spores in a fossil fern-sporangium. New Phyt., Ill, p. 18-23. 2 textfigs

1905-1 On the structure etc.. On a new type of Sphenophyllaceous cone (Sphenophyllum
fertile) from the Lower Coal-measures. Phil. Trans. Roy. Soc. London, B, CXCVIII, p. 17
-39, PL III-V, 3 textfigs.

_ 1905-2. The sporangia of Stauropteris oldhamia Binney. New Phyt., IV. p. 114-120. 2 textfigs.
_ 1906. The structure of Lepidodendron obovatum Sternberg. Ann. of Bot., XX, p. 317-319.

Scott, d. h., 1907, The present position of Palaeozoic Botany. Progressas Rei Botanicae. i, p. 139-217, 37 figs.

—nbsp;1908, Studies in fossil Botany, Sec. Ed., I, p. I-XX, 1-363, figs 1-128.

—nbsp;1909-2, Dr. Paul Bertrand on the Zygopterideae. New Phyt.. VIII, p. 266-272.

—nbsp;1918, The structure of Mesoxylon multirame. Ann. of Bot.. XXXII, p. 437-457, PI. XI-XIV, 2

. — 1920, Studies in fossil Botany, Third Ed., I, p. I-XXIII, 1-434, figs 1-190.

—nbsp;1924, Extinct plants and problems of Evolution, p. I-XIV, 1-240, 63 figs.

Scott, D. H., and A. J. Maslen, 1910, On Mesoxylon, a new genus of Cordaitales. Preliminary note. Ann.
of Bot.. XXIV, p. 236-239.

Seward, A. C., 1890 (1892), Notes on Lomatophloios macrolepidotus (Goldg). Proc. Camtr. P/ji7. 5oc., VII,

—nbsp;1893, On the genus Myeloxylon (Brongn. ) Ann. of Bot.. VII. p. 1-20, PI. I-II.

—nbsp;1897, A contribution to our knowledge of Lyginodendron. Ann. of Bot.. XI, p. 65-86, PI. V-VI.

—nbsp;1899-1. Notes on the Binney-collection of Coal-measure plants. I: Lepidophloios. Proc. Cambr.

—nbsp;1899-2, Ibid., II: Megaloxylon gen. nov. Ibid.. p. 158-174, PI. V-VII, 4 textfigs.

—nbsp;1902, The so-called phloem of Lepidodendron. New Phyt.. I, p. 38-46, 2 textfigs.

—nbsp;1906, The anatomy of Lepidodendron aculeatum Sternberg. Ann. of Bot.. XX, p. 371-381, PI.

Seward, A. C. and A. W. Hill, 1900, On the structure and affinides of a Lepidendroid stem from the Cal-
ciferous Sandstone of Dalmeny, Scotland, possibly identical with Lepidophloios Harcourtii
Witham. Trans. Roy. Soc. Edinb.. XXXIX, 4, p. 907-931, PI. I-IV.
Solms-Laubach, H. Graf zu, 1887, Einleitung in die Palaeophytologie. Leipzig, p. I-VIII, 1-416, figs 1-49.
Stores, M. C. and D. M. S. Watson, 1909, On the present distribution and origin of the calcareous con-
cretions in coal-seams, known as quot;coal-ballsquot;. Phil Trans. Roy. Soc. London. CC, p. 167-
218, PI. XVII-XIX.

Stores, M. C., 1903, The quot;epidermoidalquot; layer of Calamité roots. Ann. of Bot.. XVII, p. 792-794, figs 30-32.
Stutzer. O.. 1914. Die wichtigsten Lagerstätten der „Nicht-Erzequot;. II. Kohle. Berlin, p. I-XVI, 1-345, Taf.
I-XXIX, textfigs 1-113.

Thoday. D., 1906, On a suggestion of heterospory in Sphenophyllum Dawsoni. New Phyt., V, p. 91-93,
fig. 14.

Thomas, H. HAMSHAW, 1909, On a cone of Calamostachys Binneyana attached to a leafy shoot. New Phyt..
VIII, p. 249-260, PI. I. 2 textfigs.
1909, See: ArbER. E. A. N. and H. H. ThOMAS, 1909.

—nbsp;1911. On the leaves of Calamités. (Calamocladus section). Phil. Trans. Roy. Soc. London. B.

CCII, p. 51-92. PI. III-V, 13 textfigs.
Watson, D. m S., 1906, On a quot;fernquot;synangium from the Lower Coal-measures of Shore, Lanes. Journ.

—nbsp;1907, On a confusion of two species (Lepidodendron Harcourtii Witham and L. Hickii sp. nov.)

under L. Harcourtii Witham in Williamson\'s XIX. Memoir; with a description of L. Hickii
sp. nov. Mem. Proc. Lit. Phil. Soc. Manch.. LI, 3. p. 1-22. PI. I-III.

Weiss, E., 1881, No tide: demonstration of a stem of Lomatophloios macrolepidotus. Zeitschr. Deutsch. Geol.
Ges., XXXIII, p. 354.

Weiss, F. E., 1901, On the phloem of Lepidophloios and Lepidodendron. Mem. Proc. Lit. Phil. Soc. Manch..
XLV, 20 p., 2 PI.

—nbsp;1902-1, On Xenophyton radiculosum (Hick) and on a Stigmarian rootlet probably related to Lepi-

dophloios fuhginosus (Williamson). Mem. Proc. Lit. Phil. Soc. Manch., XLVL 3, 19 p., 3 PI.

—nbsp;1902-2, The vascular branches of Stigmarian rootlets, Ann. of Bot., XVI, p. 559-573, PI. XXVI.

—nbsp;1902-3, A biseriate halonial branch of Lepidophloios fuliginosus. Trans. Linn. 5oc.. 2, Bot., VI, 4,

—nbsp;1907, The parichnos in the Lepidodendraceae. Mem. Proc. Lit. Phil. Soc. Manch., LI, 2, 21 p., 1 PI.

—nbsp;1913, The root-apex and young root of Lyginodendron. Mem. Proc. Liï. P/ii7. 5oc. Manc/2., LVII

Wild, G. and }. Lomax, 1900, On a new Cardiocarpon-bearing strobilus. Ann. of Bot., XIV. p. 160.
Williamson. W. C.. 1871-1, On the organization of the fossil plants of the Coal-measures. I. Phil. Trans.
Roy. Soc. London, CLXI, p. 477-510, PI. XXIII-XXIX.

—nbsp;1871-2, On the structure of the woody zone of an undescribed form of Calamites. Mem. Proc.

—nbsp;1871-3, On a new form of Calamitean Strobilus from the Lancashire Coal-measures. Mem. Proc.

—nbsp;1872-1, On the organization etc. II, Phil. Trans. R.S.L., CLXII, p. 197-240, PI. XXIV-XXXI.

—nbsp;1872-2, On the organization etc. III. Phil. Trans. R. S. L., CLXII, p. 283-318, PI. XLI-XLV.

—nbsp;1872-3, On the structure of the Dicotyledons of the Coal-measures. Rep. 41st meeting Brit. Ass.,

—nbsp;1872-4, Notice of further researches among the plants of the Coal-measures. Proc. R.S.L., XX,

—nbsp;1873, On the organization etc. IV. Phil. Trans. R. S. L., CLXIII, p. 377-408, PI. XXII-XXXI.

—nbsp;1874-1, On the organization etc. V. Phil. Trans. R. S. L., CLXIV, p. 41-81, PI. I-IX.

—nbsp;1874-2, On the organization etc. VI. Phil. Trans. R. S. L., CLXIV, p. 675-703, PI. LI-LVIII.

—nbsp;1876-1, On the organization etc. VII. Phil. Trans. R. S. L. CLXVI, p. 1-25, PI. I-VII.

—nbsp;1876-2, On some fossil seeds from the Lower Carboniferous beds of Lancashire. Rep. Brit. Ass.,

—nbsp;1877, On the organization etc. VIII. Phil. Trans. R. S. L., CLXVII, p. 213-270, PI. V-XVI.

—nbsp;1878, On the organization etc. IX. Phil. Trans. R. S. L., CLXIX, p. 319-364, PI. XIX-XXV.

—nbsp;1880, On the organization etc. X. Phil. Trans. R. S. L., CLXXI, p. 493-539, PI. XIV-XXI.

—nbsp;1881, On the organization etc. XI. Phil. Trans. R. S. L.. CLXXII, p. 283-305, PI. XLVII-LIV.

—nbsp;1883, On the organization etc. XII. Phil. Trans. R. S. L., CLXXIV, p. 459-475. PI. XXVII-

—nbsp;1886, A monograph on the morphology and histology or Stigmaria ficoides. The Palaeontogra-

—nbsp;1887-1, Note on Lepidodendron Harcourtii and L. fuliginosum. Proc. R. S. L., XLII, p. 6-7.

—nbsp;1887-2, On the true fructification of the Carboniferous Calamites. Proc. R. S. L., XLII, p.

—nbsp;1887-3, On the organization etc. XIII. Phil. Trans. R. S. L., CLXXVIII, p. 289-304, PI. XXI-

—nbsp;1888-1, On the organization etc. XIV. Phil. Trans. R. S. L., CLXXIX, p. 47-57, PI. VIII-XI.

—nbsp;1888-2, On the organization etc. XV. Phil. Trans. R. S. L., CLXXIX, p. 155-168, PI. I-IV.

—nbsp;1889. On the organization etc. XVI. Phil. Trans. R. S. L. CLXXX, p. 195-214, PI. V-VIII.
1890, On the organization etc. XVII. Phil. Trans. R. S. L., CLXXXI, p. 89-106, PI. XII-XV

—nbsp;1891-1, On the organization etc. XVIII. Phil. Trans. R. S. L., CLXXXII, p. 255-265, PI. XXV-

—nbsp;1891-2, General, morphological, and histological index to the authors collective memoirs on the

fossil plants of the Coal-measures. I. Mem. Proc. Lit. Phil. Soc. Manch., 4, IV„ p. 53.
1893-1, On the organization etc. XIX. Phil. Trans. R. S. L., CLXXXIV, p. 1-38, PI. I-IX.

—nbsp;1894-2, Correction of an error of observation in Part XIX of the author\'s memoirs on the organi-

zation of the fossil plants of the Coal-measures. Proc. R. S. L., IN, p. 422-423.

—nbsp;1895, On the light thrown on the question of the growth and development of the Carboniferous

arborescent Lepidodendra by a study of the details of their organization. Mem. Proc. Lit.

Phil. Soc. Manch., 4, IX, p. 31-65.
Williamson, W. C. and M. M. HaRTOG, 1882, Les Sigillaires et les Lepidodendrées. Ann. Sci. Nat., Bot..

Williamson, W. C. and D. H. Scott, 1894, Further observations on the organization of the fossil plants
of the Coal-measures. I, Calamités, Calamostachys, Sphenophyllum. Phil. Trans. R. S. L.,
CLXXXV, p. 863-959, PI. lxxii-LXXXVI.

—nbsp;1895, Ibid., II, The roots of Calamités. Phil. Trans. R. S. L., CLXXXVI. p. 683-701, PI. XV-

—nbsp;1896, Ibid., Ill, Lyginodendron and Heterangium. Phil. Trans. R. S. L., CLXXXVI, p. 703-779.

Yabe, H and S ENDO 1921, Discovery of stems of a Calamités from the Palaeozoic of Japan. Sci. Rep. of the

Tohoku Imp. Univ., Sec. Ser., (Geol.) V, 3, p. 93-95, PI. XV, 1 textfig.
ZalesskY, M. D., .1908, Etude sur la structure anatomique dun Lepidostrobus. Mém. Com. Geo/., Nouv. Ser.,
46, p. 19-33, PI. I-IX.

—nbsp;1909, On the internal structure of the stem of the type of Lepidodendron aculeatum Sternberg and

\' Sigillaria Boblayi Brongniart. Mem. of the Imp. Russ. Mineralog. Soc., XLVI, 2, p. 273-
328, PI. IV-X, 7 textfigs.

—nbsp;1910-1, Sur les concretions calcaires (coal-balls) dans les couches de houille du terrain houiller

du Donetz. Bull, de la Soc. des Naturalistes d\'Orel, 2, 1910, p. 71-77. (Russian with French

—nbsp;1910-2 A propos de la trouvaille de débris végétaux à structure conservée dans une des roches sou-

jacentes au calcaire S (I 3) de la coupe générale des dépôts carbonifères du bassin du Donetz.
Bull, de l\'Acad. Imp. des Sci. St.-Pétersb.. 1910, p. 447-449. (Russian with French title.)

_ 1910-3, On the discovery of the calcareous concretions known as coal-balls in one of the coal-seams

of the carboniferous strata of the Donetz basin. Bull. Acad. Imp. Sci. St.-Pétersb., 1910, p.

—nbsp;• 1911, Etudes Paléobotaniques, I. Structure du rameau du Lepidodendron obovatum Sternberg et

note préliminaire sur le Caenoxylon Scotti nov. gen. et spec. St.-Pétersbourg, 1911, 16 pages.
2 Pl., 4 textfigs.

_ 1912, Ibid., I, supplément. Sur le coussinet foliairé du Lepidodendron obovatum Sternberg. St.-

Pétersbourg, 1912, p. 17-21, 1 Pl.
Zeiller, r., 1900, Eléments de Paléobotanique. Paris, p. 1-417, figs 1-210.

Tusschen de Isoetineae en de Lycopodineae bestaan slechts habitueele overeenkomsten.

Het voorkomen van eenzelfde fossiele flora in gebieden met verschillende breedtegraad
bewijst niet. dat de daarbij behoorende afzettingen synchronisch zijn.

Voor het bestaan hebben van een tropische of subtropische altijd-groene loofboom-
flora in de poolstreken is het noodzakeUjk aan te nemen, dat de relatieve ligging van deze
gebieden ten opzichte van de polen van de huidige verschillend moet zijn geweest.

De sphenothorax-theorie van Feuerborn inzake de segmentatie van de insecten-thorax
is absoluut onhoudbaar.

De bezwaren, door Fraülein von Ubisch tegen de statolithen-theorie ingebracht, zijn
niet afdoende (Biol. Zentralbl., 1928, p. 172).

Het is ongewenscht botanische excursies van groepen studeerenden of liefhebbers te
brengén naar vindplaatsen van zeldzame planten.

De beste vooropleiding voor alle faculteiten is de natuurwetenschappelijke afdeeling
van de Hoogere Burgerschool gevolgd door een aanvullingsexamen in Latijn en Grieksch.

Het is niet wenschelijk, dat proefschriften ter verkrijging van den graad van Doctor
in de exacte wetenschappen aan een Nederlandsche Universiteit in het Nederlandsch ge-
schreven zijn, tenzij zij voorzien zijn van een zeer uitgebreid résumé in een der meest ver-
spreide Europeesche talen.

56-60 : Lepidodendron aculeatum - 61 : Amyefon radicans - 62-65 : Cordaites Felicis

66-70 : Lepidostrobus oldhamius - 71 : Lepidostrobus foliaceus - 72 : S/r^mono arachnoidea

85-86 : Diploxylon 144 — 87-88 : Diploxylon 89
89 : Lepidodendron obovatum - 90 : Lepidophloios macrolepidotus

91-91 bis : Lepidophloios macrolepidotus - 92 : Stigmaria arachnoidea - 9l^ Stigmaria cf ? hacuperisis
94 rSigillariopsis laevis - 95 : ^azocar^on cf.nbsp;- 96 : Sz^r//ar.a mamxUarts

105 : Ca/amc7cs communis - 106 : Calamostachys oldhamia - 107 : Cafomo^facftys B.nn^ona
108-109 : Palaeostachya vera - 110-112 : Botryopteris tridentata

113-114 : Etapteris Scotti - 115 : Ankyropteris westphaliensis - 116-117 : Stauropteris oldhamia

129-132 : Mesoxylon muUirame — 133-134 : Anachoropteris Williamsoni
135 : Anachoropteris pulchra — 136 : Anachoropteris rotundata

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