XIV. 

 SPHENOPHYLLEAE. 



THE Sphenophyllae are members of one of the most remarkable among 

 the leading genera of the Middle and Upper Coal-measures. They do not 

 pass beyond the Lower Rothliegende, in which they have been found at 

 Autun, and it is doubtful whether the species described from older deposits 

 belong to the group. This is especially the case with Sphenophyllum 

 tenerrimum, Ett. 1 from the Culm, the beds of Ostrau and Waldenburg, 

 which may even be a Calamites, and be parallel with Archaeocalamites 

 radiatus, and still more with the rather obscure and dubious Devonian 

 remains which Dawson 2 named Sphenophyllum antiquum. 



The genus, owing to its striking appearance, has been repeatedly 

 figured by the old authors ; a copious collection of the older literature and 

 of the descriptions of the several species is given by Coemans and Kickx 3 . 

 The slender stems, which in the impressions are simply a thin rind of coal, 

 are articulated, and bear at the nodes leaves in whorls, and branches 

 standing singly and according to the statements of authors in the axils of 

 the leaves. The stems are usually marked by rather strong ridges and 

 furrows, which always run unaltered and uninterrupted over the nodes. 

 Each whorl consists of at least six leaves, often of more, and in that case the 

 number is always a multiple of six, beingtwelve, eighteen, or even twenty-four. 

 On this point I find that all authors virtually agree. The single sessile leaf 

 broadens and becomes wedge-shaped from a narrow base, and is obtusely 

 rounded at the anterior margin and sometimes toothed (Sphenophyllum 

 Schlotheimii, Brongn., S. emarginatum, Brongn.), or else it is repeatedly 

 and dichotomously divided with more or less deep incisions into broader or 

 narrower points. The lamina of the leaf is traversed by simple unconnected 

 nerves of equal size, which bifurcate once or repeatedly, and are slightly 

 divergent. According to Schenk 4 one nerve only enters the base of the 

 leaf. This is certainly true of the form which he has described (Spheno- 

 phyllum emarginatum, Brongn., var. truncatum, Schpr), but I should doubt 



1 Stur (5), p. 107. 2 Dawson (1\ p. 32, t. 5, ff. 61, 62. 3 Coemans et Kickx (1). 



Schenk (2), p. 220, with figure. 



