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MUS. COMP. ZOOL.
LIBRARY

DEC 24 1969

HARVARD
UNIVERSITY;

POSTILLA

PEABODY MUSEUM
YALE UNIVERSITY

NUMBER 133. 9 JUNE 1969.

A PROBABLE PTERIDOSPERM
WITH EREMOPTERID FOLIAGE
FROM THE ALLEGHENY GROUP
OF NORTHERN PENNSYLVANIA

T. DELEVORYAS
T. N. TAYLOR

POSTILLA

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A PROBABLE PTERIDOSPERM WITH EREMOP-
TERID FOLIAGE FROM THE ALLEGHENY GROUP
OF NORTHERN PENNSYLVANIA

T. DELEVORYAS

Department of Biology and Peabody Museum of Natural
History, Yale University, New Haven, Connecticut, 06520

i Ne TAYLOR

Department of Biological Sciences,
University of Illinois at Chicago Circle
Chicago, Illinois, 60680

ABSTRACT

Compressed fossilized foliage most comparable to that of Eremop-
teris zamioides (Bertrand) Kidston occurs in shale associated
with coal in the Allegheny Group in northern Pennsylvania.
In association with this foliage are abundant samaropsid seeds
and small, apparently microsporangiate organs. Although close
proximity of disconnected plant parts as fossils is not evidence in
itself that these plant parts were originally connected, it is tempting
to believe that these leaves, seeds, and microsporangia were parts
of the same species. Furthermore, there have been a number of
previous reports associating samaropsid seeds with Eremopteris.
Additional frondlike structures with the same basic construction
as the vegetative eremopterid leaves have been found; these offer
information concerning the possible mode of attachment of the
fertile organs.

POSTILLA 133: 14 p. 9 JUNE 1969.

2 POSTILLA

INTRODUCTION

In his efforts to reconstruct plant life of the past, the paleobotanist
is thwarted by the frequently fragmentary nature of plant remains
in the rocks. It becomes essential to piece together these fragments
into the proper whole by whatever valid means are available.
Simple association of fragmentary plant parts in the fossil record
cannot be used as definite proof that these parts were constituents
of the same living plant. Obviously, the only conclusive proof
involves organic connection or the demonstration that some
peculiar or unique structural feature, such as that of the epidermis,
is found in all the scattered parts. However, when associa-
tions occur with sufficient frequency, it is worth mentioning them
and suggesting what the whole plant might have looked like if the
pieces belong together.

Seward (1917, p. 170) figured a specimen of Eremopteris
artemisaefolia (Sternberg) Schimper in close association with
which are compressions of seedlike bodies referred to as Sama-
ropsis acuta Kidson. This association was consistent enough for
Seward to feel that the seeds were part of the plant that is known
from these Eremopteris leaves. The seeds were flattened and
bilaterally symmetrical, with two small distal hornlike projections.

Later Corsin (1928) described leaves like those of Eremopteris
zamioides (Bertrand) Kidston from the Upper Westphalian of
northern France. Associated with these fronds were fructifications
that he assumed were part of the same plant that bore the leaves.
Seeds, much like those figured by Seward (1917), were frequent,
as were structures thought to be microsporangiate organs. These
presumed microsporangia have small, radiating appendages, and
look like small flowers. Parts of the foliage were also reported
to have attached to them small, ovulelike structures in two rows
along each pinna. These presumed ovulate structures, however,
are immature and do not resemble the dispersed seeds. Corsin
placed the entire assemblage into a new genus “Preridozamites’,
which he considered to be a pteridospermous plant.

Specimens of Carboniferous plants from Durham, England, in
the Paleobotanical Collections of the Peabody Museum of Nat-
ural History include some Eremopteris artemisaefolia. On the
same slabs, in close association with the leaf pieces, are bilaterally
flattened seeds like those of Samaropsis acuta figured by Seward.

A PROBABLE PTERIDOSPERM 3

Thus, although nothing conclusive can be stated about the
relationships of these vegetative and fertile plant parts, one is
easily led to believe that very likely they belonged together,
and that at least some species of Eremopteris were pterido-
spermous.

DESCRIPTION OF NEW MATERIAL

Recent collections of Pennyslvanian plant compressions from
northern Pennsylvania have further emphasized the possible rela-
tionship of platyspermic seeds and Eremopteris foliage. The
material was collected in a strip mine about 4 km (2.5 miles)
northwest of English Center, Lycoming County, Pennsylvania.
The coal is thought to belong to the Allegheny Group and appears
to be one of the easternmost outliers of that group in Penn-
sylvania. Plant fossils occur in a finely bedded gray shale that
splits apart easily into thin sheets. Plant material is delicately
preserved, although no cuticle appears to be present. Specimens
are best examined submerged in xylene; photographs of the
material included in this paper were taken in that fashion.

Common fossils at this site include Sphenopteris obtusiloba
Brongniart and S. spiniformis Kidston, Neuropteris heterophylla
Brongniart, Lepidodendron obovatum Sternberg, Lepidostrobus
sp., and scattered Lepidocarpon megasporophylls.

Leaves of Eremopteris that closely resemble E. zamioides are
extremely abundant. We believe that most of the specimens col-
lected are entire leaves. They generally measure 14-20 cm in
length; at the base of the rachis there seems to be a sharp line
of abscission. Frequently, large numbers of these leaves are found
closely aggregated, and all are extremely similar in general size
and shape (Fig. 1). An alternative explanation of the abruptly
truncated leaflike structures would be to regard them as pinnae
of a much larger frond, the parts of which abscissed. Because most
of the leaves found are the same size, and because it is difficult to
visualize a pinnately constructed frond with pinnae identical
throughout, we are inclined to regard these structures as entire
fronds.

Pinnae are alternate to subopposite; the base of the rachis is
generally naked, and lowest pinnae are smaller than the largest
ones, which occur about half the distance up the rachis (Fig. 2).
Largest pinnae may reach 5 cm in length. Pinnules are narrow

4 POSTILLA

FIG. 1. Eremopteris zamioides. Slab with numerous leaves preserved.
Intervals on scale at lower left are millimeters. YPM Paleobot. 1105.
(Numbers refer to specimen numbers in the Paleobotanical Collections,
Peabody Museum of Natural History )

A PROBABLE PTERIDOSPERM 5

FIG. 2. Eremopteris zamioides. Nearly complete leaf. YPM Paleobot. 1106.

6 POSTILLA

and incised; pinnae at the distal end of the frond may be entire
or occasional ones may have some incising. Venation is the open
dichotomous type characteristic of Eremopteris, with no apparent
midvein in the pinnules (Fig. 3).

Seeds found in close proximity to the Eremopteris foliage are
conspicuously flattened and bilateral, with two prominent distal
spines (Figs. 4, 5). They are quite unlike Samaropsis acuta seeds
and resemble somewhat the seeds called Ptilocarpus bicornutus
by Lesquereux (1879, Pl. 85, fig. 51) and later (1880; p:565)
Cardiocarpus bicornutus. This seed material, described by Les-
squereux as having coniferous affinities, originated in the shale
above coal in Coshocton, Ohio. In many respects these seeds
resemble the Lower Carboniferous genus Lyrasperma Long (1960)
from Scotland.

Shape of the new seeds is highly variable, perhaps partly due
to natural variation and partly to varying degrees of compression
during fossilization. Furthermore, these different shapes may
represent different ontogenetic stages. A central oval or elliptical
portion, possibly representing the outline of the inner testa, is
discernible on the compressed seeds. A flange, or wing, surrounds
this central body, as in many species of Samaropsis. This wing, of
course, could represent either a true flangelike extension of the
integument, or it may simply be the flattened sarcotesta after
compression. Proximally, the integument is extended into an
acuminate process, the end of which represents the point of
attachment. Length ranges from 10 to 15 mm, and width from
4 to 6 mm in the primary plane (not including the distance
between the flaring distal projections). In many specimens a con-
spicuous line runs axially along each of the flat faces. These lines
could represent vascular bundles, or they may reflect the fact
that the integument may be composed of two symmetrical halves
(as in Lyrasperma), with the lines on the flat faces representing
sutures.

Generally the seeds are in the form of thin, carbonaceous films,
but rarely a megaspore membrane is present. One such seed
(Fig. 6) had split along the major plane of symmetry exposing
the spore membrane.

Possible microsporangiate organs associated with the foliage and
seeds are similar to those decribed by Corsin (1928) for his
“Pteridozamites” material. They are always found detached, most

A PROBABLE PTERIDOSPERM 7

FIG. 3. Eremopteris zamioides. Terminal part of a leaf showing detail of
venation. * 1.9. YPM Paleobot. 1107.

FIG. 4. Platyspermic seeds with distal hornlike projections and acuminate
proximal region. * 1.3 YPM Paleobot. 1108.

8 POSTILLA

FIG. 5. Platyspermic seeds in close association with a frond of Eremopteris
zamioides. X 1.3. YPM Paleobot. 1109.

FIG. 6. Seed split along the primary plane to reveal the central megaspore
membrane. 11.5. YPM Paleobot. 1110.

A PROBABLE PTERIDOSPERM Y)

likely after having shed pollen, scattered over the bedding plane
surfaces, generally in clusters. In their mature state they look
somewhat flowerlike or star-shaped, probably the result of a cap-
sulate structure having split open at the time of pollination (Fig.
7). Maceration of these presumed fructifications, unfortunately,
yielded no pollen grains.

If the associated plant parts described above are, indeed,
detached organs of the same plant, we should suggest possible
means of attachment, and what the entire plant might have looked
like. Obviously, if the plant was actually a pteridosperm, by
definition the reproductive structures must have been borne on
leaves. There is nothing about the eremopterid foliage described
thus far that indicates the possible mode of attachment. Very
significant, however, are additional foliar structures, again in close
association with the other parts, that are generally smaller than
tne typical vegetative leaves, but that have the same kind of
construction, that is, a main rachis with pinnately borne laterals,
oppositely or suboppositely arranged. On these laterals (pinnae )
are short stubby projections that seem to be abruptly truncated
as if representing structures from which some other bodies had
fallen off (Figs. 8, 9). It is on just such structures that the seeds
and pollen-bearing organs could have been borne. Furthermore,
there appear to be at least two sizes of these presumed fertile
leaves; the larger (up to 13 cm in length) could conceivably have
represented the megasporophylls, while the smaller (generally
about 5 cm long) could be microsporophylls. It might be argued
that these presumed fertile leaves are actually immature vegetative
fronds, and that subsequent development would have resulted
in differentiation into the more typical eremopterid frond form.
In the same beds, however, are specimens that are obviously
immature fronds (Fig. 10), and in spite of their relatively young
age they are conspicuously different from the probable fertile
leaves and actually have much in common with the fully mature
adult vegetative leaves.

RECONSTRUCTION

From these various parts, it is tempting to envisage a pteridosper-
mous plant, perhaps not too tall, with eremopterid foliage borne
on the stem. We conclude that these plants were deciduous,

10 POSTILLA

dropping the leaves in their entirety, although not necessarily
at seasonal intervals. In most plants with fernlike leaves the
fronds generally wither and shrivel before falling from the stem.
These eremopterid leaves, on the other hand, appear to be little
distorted, nicely flattened, with an abrupt truncation at the base
of the rachis. Thus, the lower part of the plant would be naked,
with functional foliage at higher levels. Elsewhere on the plant
there may have been modified leaves, with the same structural
plan as that in the vegetative leaves, but much reduced and bear-
ing either microsporangia or seeds. A possible reconstruction of
such a plant is presented in Figure 11. It must be emphasized,
however, that this drawing represents only one of the several pos-
sible, logical combinations of the various structures.

NOMENCLATURE

If, indeed, all of these parts are thought to belong to the same
kind of plant, a single specific name should be used for the entire
assemblage. Corsin considered his diverse plant fragments to
represent portions of a single species to which he applied the
name ‘“Pteridozamites’ zamioides P. Bertrand. However, for a
number of reasons, this move cannot be accepted. First, there is no
generic diagnosis in Corsin’s paper for P. zamioides, hence the
generic name is invalid. A second reason for rejecting the com-
bination P. zamioides P. Bertrand is that Bertrand did not institute
the name. Third, Corsin had no more evidence than we do that
all of these parts are pieces of the same plant. As mentioned
above, One is tempted to believe that because of their constant
association all the separate parts logically belong to the same
plant, but more concrete evidence must be at hand to prove
the connection. If our new material consisted of remains only of
the parts described in this paper, then it would be more certain
that these parts are all from the same kind of plant. There is an
abundance of other remains, however, including sphenopterid
leaves, so there is also the possibility that the seeds and mi-
crosporangia were borne on leaves of that type. For that reason
we have not formally assigned all of the parts to one name.

DISCUSSION

Since we are not willing to agree with Corsin’s assigning the
various isolated parts of his material to a single name on the

A PROBABLE PTERIDOSPERM 1]

Possible microsporophyll, natural size. YPM Paleobot. 1112.

8
FIG. 9. Possible megasporophyll, natural size. YPM Paleobot. 1113.

FIG. 10. Eremopteris zamioides. Two immature vegetative fronds. Natural
size. YPM Paleobot. 1114.

72 POSTILLA

fe
SASS SA,
WZ
Lath Sees
yp As y# —F¥ g

——

FIG. 11. Suggested reconstruction of a pteridospermous plant with eremop-
terid leaves and fertile structures such as those described in this paper.

A PROBABLE PTERIDOSPERM 13

grounds that the parts were not actually attached, we must justify
our presumption in presenting the reconstruction in this paper.
Certainly we are agreed that association in itself must be ap-
proached with caution. On the other hand, this is not the first
time that the conspicuous association of platyspermic seeds with
eremopterid foliage was noted. Reports by previous authors,
together with this one, add up to evidence that cannot be dis-
missed lightly.

There is considerable precedent for the attachment of seeds to
fernlike foliage in the Paleozoic. White’s (1904) Wardia fertilis is
an example of flattened seeds attached to foliage similar to that
of Adiantides. Emplectopteris triangularis (Halle, 1927) is another
example of platyspermic seeds borne on fernlike foliage, although
in that case, seeds were borne on laminar surfaces. There are
numerous other instances of seeds borne on foliage, but in most
of the other reports, the seeds were radially symmetrical.

If such a plant as that suggested in our reconstruction did
exist, what are its affinities? Platyspermic seeds are generally
thought to be conifer-related, but the structure of eremopterid
foliage is certainly far from a coniferophytic leaf morphology.
Actually, bilaterally symmetrical seeds are an early type, having
been reported by Long (1960) in the lower Carboniferous of
Scotland. The fragments of axes on which are borne the various
seeds with which Long worked are typically leafless, making it
tempting to suspect that in some seed plants, at least, the seeds
evolved before the appearance of leaves. If such is the case, it
would be impossible to categorize these Mississippian plants as
coniferophytes or pteridosperms. Eggert and Delevoryas (1960)
suggested that bilateral symmetry of seeds need not be a reflection
of natural affinities. Conostoma Williamson, a pteridosperm genus
based on seeds with generally radial symmetry includes one species
—C. platyspermum (Graham, 1934) — that is bilaterally flat-
tened. Thus, platyspermic samaropsid seeds need not be considered
uniquely coniferophytic, and their probable presence on eremop-
terid leaves need not be considered anomalous.

As work progresses on late Paleozoic and early Mesozoic
pteridosperms, one cannot help but be impressed with the tre-
mendous diversity of leaf types, seed structure, pollen-bearing
organs, and vegetative anatomy. It is becoming increasingly
obvious that the class Pteridospermopsida (or other nomenclatural

14 POSTILLA

equivalent) may ultimately be separated into a number of inde-
pendent groups. Much parallel evolution of seed plants must have
occurred during the Paleozoic, resulting in a number of groups
of plants with fernlike foliage on which were borne seeds and
pollen-bearing structures. The old class “Gymnospermae” has
been shown to be an artificial assemblage (Arnold, 1948) with
naked seeds being the only important feature in common.
Similarly, we feel that before long the pteridosperms as they are
now known cannot be held together as a natural entity solely by
the character of seeds borne on fernlike foliage.

ACKNOWLEDGMENTS

We are grateful to Miss Ward Whittington for her rendition of
Figure 11. Research for this project was supported by National
Science Foundation grant GB-5911X to T. D. and grant GB-6834
tooT. N: 1

LITERATURE CITED

Arnold, C. A. 1948. Classification of gymnosperms from the viewpoint
of paleobotany. Bot. Gaz. 110: 1-12.

Corsin, P. 1928. Sur les fructifications et la position systématique
de Sphenopteris zamioides P. Bertrand. Ann. Soc. Geol. Nord 53:
222-230.

Eggert, D. A., and Delevoryas, T. 1960. Callospermarion —a new seed
genus from the Upper Pennsylvanian of Illinois. Phytomorphology
10: 131-138.

Graham, R. 1934. Pennsylvanian flora of Illinois as revealed in coal balls.
I. Bot. Gaz. 95: 453-476.

Halle, T. G. 1927. Paleozoic plants from central Shansi. Geol. Surv.
China, Palaeont. Sinica, Ser. A, 2 (Fasc. 1): 1-316.

Lesquereux, L. 1879. Atlas to the coal flora of Pennsylvania and of the
Carboniferous Formation throughout the United States. Second Geol.
Surv. Pennsylvania: Rept. of Progress. 18 p., 85 pls.

1880. Description of the coal flora of the Carboniferous
Formation in Pennsylvania and throughout the United States. Vol. 2,
p. 355-694. Second Geol. Surv. Penn.: Rept. of Progress.

Long, A. G. 1960. On the structure of Samaropsis scotica Calder (emended)
and Eurostoma angulare gen. et sp. nov., petrified seeds from the
Calciferous Sandstone series of Berwickshire. Trans. Roy. Soc. Edin-
burgh 64: 261-280.

Seward, A. C. 1917. Fossil plants. Vol. 3. Cambridge Univ. Press. 656 p.

White, D. W. 1904. The seeds of Aneimites. Smithsonian Misc. Coll.
47: 322-331.

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