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" Reprinted from the Gamulinn Record ofScieiuie, July, 1896."

Nematophyton CKASSUM.
By D. P. Pknhallow.

Since my last surnnaary of the genus Nematophyton, in
wliich eight species were enumerated,* additional material
has been received, which, on the basis of more ample and
more perfectly preserved specimens, serves to extend and
confirm our previous- knowledge of certain species.

The specimen now under consideration was received
from Mr. F. K. Mixer, of the Buffalo Society of Natural
Sciences, who reports that it was obtained from the upper
part of the water-lime gi'oup (Lower Helderberg) of the
Upper Silurian. Heretofore the occurrence of this genus,
at so low a horizon, has been confined to N. Hicksii,
N. Logani and, more recently, N. Storriei, all of which
have been from European localities, while N. Logani
has also been found sparingly and in fragmentary
specimens at Cap Bon Ami, New Brunswick.

This is the first timo the species now under consideration
has been observed in the Silurian of America, the lowest
and only horizon heretofore recorded being Middle Erian.
It, therefore, affords important testimony bearing upon
the great antiquity of the genus as a whole, and of
this species in particular.

> Aim. Bot. X., 41, 1890.

152 Canadian Becwd of Science.

The specimen obtained by Mr. Mixer represents the
base of tbj stem or stipe, and in this respect it is similar
to the recently described specimen of N. Ortoni.^ It
measures 56 centimeters long. At the top it is 7.5 cm.
broad, while at the base, where the root processes arise, it
widens out to 16.5 cm. Externally the surface is
roughened as if from the result of superficial decay, and
shows somewhat extended carbonized areas, within which
the material separates in smaU angular fragments. In
the transverse section no concentric structure is observable.
Sections of this specimen were prepared by Dr. J. M
Clarke, of Albany, N.Y., and forwarded to me for study.
They represent a fairly well preserved structure, and even
a hasty examination served to show that they exhibited
several elements of interest.
Transverse Section.

The structure is soraev<rhat altered, in consequenqe of
which ths large cells are, to some exteac, wanting in
a sharply defined outline, but nowhere was there that
extreme alteration met with in specimens of the same
species as formerly obtained from the Hamilton group
of New York. Nevertheless, the alteration has been
carried sufficiently far to render the small hyph* lying
between the large cells, tr a great extent unrecognizable.
The best material representing this species, heretofore
studied, was that originally collected by Dr. Bell from
Gasp^, but it was in small fragments and did not permit of
extended s«udy. It, nevertheless, showed the large cells
of the medulla to be very perfectly preserved, and the
hyphse also, to be unaltered in form.» It was upon a
study of this material that the diagnosis of the species
was first based. Later, a revision of the Celluloxylon
primffivum of Dawson, as represented by material from the
HamUton group of New York, collected by Dr. J. M.

I Ann. Bot. X.,«l,I8»e.

« Tr»u«. B. Soc. VII., W., 20, 21.

Nematophyton crassum.

153

lents the
is similar
;oni/ It
is 7.5 cm.
23 arise, it
lurface is
lecay, and
hill which
lents. In
)bservable.
Dr. J. M
for study.
!, and even
T exhibited

equenqe of
wanting in
there that
f the same
Iton group
has been
yph* lying
ecognizable.
, heretofore
. Bell from
ot permit of '
8 large cells
ed, and the
was upon a
the species
Celluloxylon
rial from the
y Dr. J. M.

Clarke, showed that this plant was referrable to N.
craosum, but that it had been highly altered by crjstalli-
zation.* More recently, material collected by Prof. C. S.
Prosser from the Hamilton group of New York, furnished
specimens much more perfectly preserved, but yet much
altered by crystallization.* From this it is to be observed
that the excellent state of preservation of the material
now at hand, affords excellent opportunities for verification
of the previous diagnoses.

The cells of the Medulla are large, ranging from
40 ,i.-62 fi. broad, but are chiefly rather uniform in size, and
average about 56 /i. in diameter. This, it will be observed,
is rather larger than observed in former specimens of this
species, which showed a range of 23 fi.-4Q /*. in one case'
and 32 (U.-39 /i. in another.^

The entire structure is rather lax — not so much so
as in N. laxum and N. Ortoni, but closely comparable
with previous specimens of N. crassum. Medullary spots
are numerous and irregularly distributed. They are of
an irregularly rounded or oblong form, and appear to
range from 174 ft. to 261 /i. in diameter. Here and there
they seem to have, undergone exceptional alteration
leading to the formation of spherical cavities about 436 /u
in diameter. They are, however, in most cases, occupied
by a somewhat loose plexus of hyphaj having a somewhat
variable diameter, ranging upwards from 4.68 ^ — similar
in general character and size to the hyphae lying betwflftn
the large cells of the medulla.

Even without the aid of a magnifying glass, a certain
concentric structure with broad zones is apparent in
the transparent section, but this is by no means as cl«^arly
defined as in N. Logani. Under a magnifying power
of moderate strength, this appearance entirely disappears,

I 1. c. VII., iv., 25.

I Proo. U.S. MaV Hut., XVI., 116.

• Proc. U.S. Nat, Hnt., XVI., 116.

« Ti»n». R. Boo. Can., VII., Iv., 20-23, 29.

154

Canadian Record of Science.

and it is extremely difficult to determine precisely upon
what it depends, but it seems probable that it is
determined by a peculiar disposition of the cells in relation
to the medullary spaces.

Large transverse sections also exhibit radial fissures due
to shrinkage, but there appears to be a total absence of
those radial bands simulating medullary rays, so con-
spicuous in N. Logani. On the other hand, the medullary
spots, already described, are connected radially and
tangentially by more continuous and open tracts as
medullary spaces, which thus form a sort of netted system
between the various sub-divisions of which the large cells
lie in distinct and often more or less rounded groups.
This distribution of the elements gives the transverse
section a very characteristic appearance. It had already
been noted in the previously described specimens of N.
crassum, but owing to the very limited area of the Oaspe
sections, and the highly altered character of the specimens
from the Hamilton group, a proper description was not
possible, and this structural feature was, therefore, omitted
from the diagnosis. It is, nevertheless, an important
diagnostic element, under the present circumstances of
limited material, since it seems to definitely differentiate
this species from all the others.
Longitudinal Section.

In longitudinal section the cells of the medulla are
somewhat, strongly interlacing, while groups of a dozen or
more often cross the general direction of growth more or
less abruptly, and sometimes turn off nearly at right
angles for a short distance. These features also appear in
previously described specimens, both from . Gasp^ and
from New York. The intercellular hyphse are freely
interlacing and cross the large cells in all directions, but
their structure is so altered by decay as to render it
impossible to determine if they are septate or not.
Nowhere have trumpet hyphae been found, thus con-
firming previous observations in this respect.

Nematophyton craastim.

155

The medullary spots are, in most cases, elongated
vertically, assuming an oblong or lenticular form, two to
several times higher than broad, features also char-
acteristic of the formerly described specimens of this
species. The spots are, as in other cases, crowded with
interlacing hyphai, and into them there also project large
cells from the surrounding structure, which branch more or
less freely. These sections afford numerous instances of
branching cells, and in one spot there were found two
such cases, (figs. 1 and 2), one of which exhibited five sub-
divisions, primary and secondary, while the other showed
three primary divisions ternnnal to the parent cell.

So many are the instances of this kind, and so
varied are the dimensions of the branches, that I cannot
but consider this specimen as affording very strong
evidence in support of the conclusions already reached,
that the medullary spaces "are the special areas within
which branching is accomplished," and that it is here that
the small hyphse have their origin from the large cells of
the medulla.'

The present material is thus found to not only extend
our knowledge of the geographical range and strati-
graphical horizon of this plant, but it affords strong
corroborative testimony with respect to previous conclu-

I Torn*. B. Hoc. Can., VI., Iv.. 42; VII.. iv., L'2.
i Anil. Bot., X., 46, 18(W.

15^

Canadian Record of Science.

sions, and extends its differential characters to an
important extent. It thus becomes necessary to revise
our original diagnosis in conformity with the facts now at

hand.

Nematophyton CRA88DM (Un.) Pen.

Transverse.

Concentric structure rather obscure. Badial tracts
none. Medullary spots numerous, irregularly round or
oval, chiefly 174 ^-261 ,u broad, and connected by narrow
spaces which form a more or less distinct network,
enclosing groups of large, thick-walled ceUs. Cells of the
medulla not very compact, rather uniform, ranging from
23 ^.-62 !«. broad, chiefly about 40 ^.

Longitudinal. ' '

Cells of the ifaedulla interlacing, often in groups.
Medullary spots vertically lenticular or oblong, crowded
with smaU hyphK, 2 ^.-10 ^. broad, which arise withm
these areas from branching cells derived from the
surrounding structure.

Highly crystalline forms often show a replacement
of the normal structure by a pseudo-cellular structure

(Celluloxylon.) . , •

Found as fragments, also the base of the stipe showing

root processes. tt -li.

Middle Erian (Devonian) of Gasp6 {Bell); Hamilton
group (Middle Erian) of New York {Clarke and Pr<mer),
and the Upper Silurian (Lower Helderberg) of New York
{Mixer.)

DBSOBIPTtON OF FlOURKS.

Fig. 1. Transverse section of Nematophyton crassum,
showing the distribution of the medullary spots.

X 45.
Fig 2. Transverse section of Nematophyton crassum,
showing distribution of the medullary spaces
connecting the medullary spots, x 45.

"*rv '"t ■"■!"' ^'

RbCORD or SOIKNOB.

Plate II.

Nkmatophyton okassum.

■r:g?i''?^»iByv-'