Fossil plants, Vol. 3 : $b A text-book for students of botany and geologySeward, A. C. (Albert Charles)
Science
Fossil plants, Vol. 3 : $b A text-book for students of botany and geology
Seward, A. C. (Albert Charles)
Paleobotany
White[1003] described this species (fig. 502, G) from
Permo-Carboniferous rocks in Brazil (Rio Grande do Sul) as
_Cardiocarpon barcellosum_. The nucule is said to be cordate but, as
seen in the figure, there is no clear indication of a basal sinus: the
presence of a relatively broad ‘wing,’ as White says, entitles the seed
‘to a place in the _Samaropsis_ section of the genus.’ The author of
the species compares it with seeds described from Westphalian rocks in
Ohio[1004] and Pennsylvania[1005]. It is interesting to find a type
which is common in both Europe and North America in the western portion
of Gondwana Land. Seeds of similar form are recorded also from India,
South Africa, and Australia[1006].
_Samaropsis Seixasi_ (White).
This Brazilian species from the same beds is described by White as
_Gangamopteris_ (_Samaropsis_) _Seixasi_[1007]: it is characterised by
a small ovate nucule 8–10 mm. long and 5 mm. broad, in some specimens
surrounded by a complete ‘wing’ extending above the apex and below the
base, giving the seed an appearance similar to that of _Samaropsis_
(_Samarospermum_) _moravica_ while sometimes, as in the example shown
in fig. 502, F, the broad border is preserved only at the sides.
These seeds are abundant in the Santa Catharina beds, where they were
discovered by Dr Esdras do Prado Seixas, in association with leaves of
_Gangamopteris_, and White thinks that they were borne on the fertile
leaves of that genus which he has named _Arberia_[1008]. Although
there is as yet no proof of a connexion between _Gangamopteris_ and
seeds of this or any other type it is almost certain that it was a
seed-producing plant.
_Samaropsis Leslii_ sp. nov.
[Illustration: Fig. 503. _Samaropsis Leslii_. From Vereeniging, S.
Africa. (Mr Leslie’s Collection; nat. size.)]
The seed on which this species is founded was discovered by Mr T. N.
Leslie in the Ecca beds (Permo-Carboniferous) of Vereeniging, South
Africa, a locality from which the same geologist has obtained leaves of
_Cordaites_, _Psygmophyllum_, _Glossopteris_ and other genera[1009].
In the slightly cordate base and tapered apex (fig. 503) the nucule
agrees closely with those of European examples, but the Vereeniging
type is distinguished by its larger dimensions and by the wider border
indicating a thick sarcotesta continued basally into a stout stalk. The
apex is emarginate and a median rib marks the position of a vascular
strand. There is no evidence as to the nature of the parent-plant.
_Samaropsis indica_ (Zeiller).
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