58 Proceedings of the Royal Physical Society. 
The structure and classification of Sphenophyllum is also 
fully entered into by Renault in his “Cours d. botan. foss,”* 
by Schimper, and Schenk, who gives some good figures 
of cones of Sphenophyllum, especially that on his pl. 
xxxviii, fig. 2 (Sphenophyllum angustifolium). Some ex- 
cellent illustrations of the fructification of this genus are 
also given by Zeiller in his “Flore foss. d. bassin houil. d. 
Valenciennes.’ * 
It is not my intention to review the various opinions held 
by different writers on the systematic position of Spheno- 
phyllum, as that has been done by several of the botanists 
who have lately written on the subject, and their works are 
very accessible. After describing the Yorkshire specimens 
which form the subject of this communication, I will, how- 
ever, make a few remarks on the systematic position of the 
genus, 
SPHENOPHYLLUM, Brongt. 
Stems and branches with prominent, slightly swollen nodes, 
ribbed longitudinally, ribs not alternating at the nodes. 
Leaves in verticils, variable in number, seldom less than six 
in a whorl, cuneiform, entire or dentate, or more or less 
deeply divided into segments; or the leaves are composed of 
narrow linear, dichotomously divided segments, veins dicho- 
tomous, spreading from the base of the leaf—one veinlet 
extending into each tooth or ultimate segment of the leaf, 
Fruit strobiliform, heterosporous, terminal or lateral, cylin- 
drical, internodes short, bracts verticillate, more or less kneed, 
the sporangia being placed on the bracts close to the knee, 
or in the axil of the knee which is formed by the sudden 
uprising of the blade of the bract. Axis solid, primary 
vascular axis three-rayed or triangular, subsequently becoming 
more or less circular through increase to its periphery, and 
surrounded by a thick bark. 
1 Deuxieme Année, p. 81 et seg., 1882. 
2 Traité d. paléont. végét., vol. 1., 1869. 
3 In Richthofen’s China, vol. iv., Paleontologischer Theil. Berlin, 1883. 
4 Pp. 409, 413, pl. lxiii., figs. 4, 4a, 5, 5a, 10, 10c, Sphenophyllwm cunei- 
folium, var. saxifragefolium ; pl. lxiv., figs. 5, 5a, Sphenophyllum emargin- 
atwm, Atlas, 1886; Text 1888, 
ee 
