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
No specimens have been described which enable us to correlate with
certainty mature leaves or foliage-shoots with the petrified bud.
It is, however, not improbable that the impression from Mount Pelé
near Epinac named by Renault _Dolerophyllum Berthieri_[384] may be
correctly referred to the same genus. The type-specimen consists of
an axis, whether a rachis of a compound leaf or a shoot with simple
leaves cannot be determined, bearing partially overlapping more or less
orbicular leaves 18–20 cm. in diameter, with a _Cyclopteris_ venation.
Among other leaves of unknown affinity referred to the same genus
attention is drawn to _Dolerophyllum pseudopeltatum_ (Grand’Eury)[385]
with an orbicular lamina reaching in some specimens 22 × 19 cm.
Specimens of _Dolerophyllum pseudopeltatum_ are figured by Renault
from the Commentry coal-field[386], some of which reach a diameter
of 12 cm. The only British specimen of a leaflet of this type which
I have seen is one in Dr Kidston’s collection from the Stephanian
series, Glamorganshire. It is probable that some at least of the
impressions assigned to _Dolerophyllum_ or _Doleropteris_ would be more
appropriately included in _Cyclopteris_ or _Cardiopteris_ and may have
been borne on the axis of large Pteridosperm fronds. Grand’Eury[387]
has also called attention to the difficulty of distinguishing the
larger _Cyclopteris_ leaflets from _Dolerophyllum_. Some of the
Cyclopteroid leaflets figured by Roehl[388] on _Neuropteris_ fronds
differ but slightly from those of _D. pseudopeltatum_. The shoot
showing large leaf-scars figured by Saporta and Marion[389] as probably
the axis of a _Dolerophyllum_ may well be a piece of _Cordaites_.
[Illustration: Fig. 432. A. _Dolerophyllum Goepperti_, section of
vein. B. _Dolerophyllum Berthieri_; _s_, microspores. C. _Dolerophyllum
fertile_. D. _Dolerophyllum fertile_, microspores. (After Renault.)]
_Microsporophylls assigned to_ Dolerophyllum.
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