Fossil plants, Vol. 2 : $b A text-book for students of botany and geologySeward, A. C. (Albert Charles)
Science
Fossil plants, Vol. 2 : $b A text-book for students of botany and geology
Seward, A. C. (Albert Charles)
Paleobotany
This genus, founded by Renault on a specimen from Autun, is represented
in the Lower Coal-Measures of England by _Botryopteris hirsuta_ (=
_Rachiopteris hirsuta_ Will.), _B. ramosa_ (= _R. ramosa_ Will.[1119])
(fig. 306) and _B. cylindrica_ (fig. 305), also by _B. antiqua_ (fig.
307) from the Culm of Pettycur, Scotland.
An important characteristic of the genus is the solid stele of the stem
which agrees with that of _Tubicaulis_ and _Grammatopteris_, except in
the central or peripheral position of the smallest tracheae.
_Botryopteris forensis_ Renault[1120]. Figs. 309, B; 319, D–G.
The stem of this species from the Upper Carboniferous of St Étienne
is 1·7 cm. x 7·5 mm. in diameter. The solid stele consists of
reticulate tracheae with the smallest elements on the outer edge.
The comparatively broad cortex of the type-specimen is traversed by
a leaf-trace in an almost vertical course and by vascular strands
passing horizontally to roots. The petioles are circular in section
and their vascular strand has the form of an ω in transverse section
(fig. 319, G), the three projecting arms pointing to the axis of the
stem. Both stem and leaves bore large multicellular hairs, spoken of
by Renault as equisetiform because of the finely toothed sheaths of
which they are composed. The compound fronds had fleshy lobed pinnules
with dichotomously branched veins (fig. 309, B); stomata are said to be
confined to the upper surface, an observation which leads Renault to
describe the plant as aquatic on evidence which is hardly convincing.
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