FILICES. 147 



Grand' Eurya, Zeill. (not Stur) species of this very Saccopteris and others be- 

 longing to Desmopteris, Stur, a genus which he has figured only in the sterile 

 state. But the figure given by Zeiller shows important points of difference, 

 and as I have satisfied myself of its correctness by comparing it with the 

 original specimens. I cannot at present acquiesce in this identification. For 

 in the plants of the French author we have sori formed of erect sporangia 

 in close contact with one another, each of which is furnished with a broad 

 sharply defined annulus-band running arch-wise across the apex, which Stur 

 indeed explains as due to the state of preservation. These characters, as 

 the author l himself points out, remind us to some extent of the group of 

 Botryopterideae, which will be considered presently. But when the two 

 remains of fructification, to all appearance so unlike one another, are united 

 by their authors with the same fern-leaves, with Sphenopteris Essinghii, 

 Andr. and S. coralloides, Gutb. Gein., or S., erosa, Gutb. Gein., it may 

 be remarked that sterile leaf-forms very like one another belong to different 

 genera, and lastly that the fertile leaves of the Ferns in question differ con- 

 siderably from the sterile, and that this must render their determination 

 difficult. For the details of this controversy, on which fresh light is needed, 

 the reader should consult the original publications, and especially Zeiller's - 

 reply to Stur. 



Corda's 3 genus Senftenbergia (Fig. 13, A), which has been submitted 

 by Stur 4 to a fresh and searching examination, is the type of the Senften- 

 bergieae. The plants of this group also are by their nervation Pecopteridae 

 and Sphenopteridae ; among them for example are Pecopteris aspera,Brongn., 

 P. plumosa, Art., Sphenopteris crenata, Ldl. and Hutt., and others from the 

 Coal-measures. Of the Triassic fern-fructifications enumerated by Stur 5 

 there are none belonging to this group. The free sporangia are not col- 

 lected into sori but are found one by one on the back of the tertiary nerves, 

 forming a longitudinal row on each side of the secondary nerve. Each 

 sporangium in the typical Senftenbergia elegans is obliquely conical and 

 acuminate from a rounded base, and turns the gentler curve, on which is 

 the dehiscence-slit, towards the outside. On its stout wall at the conical 

 apex may be seen a hood-shaped annulus, which is formed of several circular 

 rows of cells lying one on another, and according to Stur is not distinctly 

 defined below. Corda 6 and after him Renault 7 and Zeiller 8 represent this 

 annulus in their drawings with a much sharper boundary-line below, and 

 make it the ground for putting the genus among Schizaeaceae. Stur rightly 

 objects to this that in Schizaeaceae the strongly individualised annulus is 

 in all cases formed of a single circular row of cells, and attaches great weight 

 to the fact that the rudimentary annulus of Senftenbergia is easy to connect 



1 Zeiller (6), p. 205. 2 Zeiller (6). :t Corda (1), t. 57. 4 Stur (5, 4, 3). 5 Stur (7). 

 Corda (1). 7 Renault (2), vol. iii, t. 12, ff. 7, 8. " Zeiller (7), t. 10, ff. 1-5. 



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