Mr E. Kidston on Sphenopteris crassa. 237 



cyclopteroid pinnules ; but on tlie greater portion of the speci- 

 men their form is rhomboidal (PL V., Fig. 2). 



The last-mentioned pinnules are composed of a number of 

 cuneate segments, united together in a fan-like manner, the 

 central one being the longest, on either side of which the 

 truncated apices of the segments give a dentate outline to the 

 pinnule, which is broadest near its centre. 



These must be regarded as the typical pinnules, the cyclop- 

 teroid pinnules only occurring towards the base of the frond- 



The difference between these two forms of pinnules is so 

 marked that, unless they had been observed on the same 

 frond, one would scarcely imagine that they belonged to the 

 same plant. 



In the figure of this species in the " Fossil Flora," the dimor- 

 phic nature of the pinnules has not been brought out, though 

 on the specimen it is distinctly shown on the uppermost pinna. 



The plant which Stur has described under the name of 

 Sphenopteris Kiowitzensis represents the middle part of a frond. 



His specimen likewise shows a dichotomy of the main axis, 

 as well as the dimorphic nature of the pinnules. 



In referring to the affinities of his specimens, Stur says : 

 " Our plant shows almost as near a relationship with Spheno- 

 pteris crassa, L. & H., from the Carboniferous Limestone of 

 Burdiehouse. This has the rachis simple below, above bifur- 

 cated, and bears pinnules, which likewise decrease from above 

 downwards (?). 



" But in the English plant the lobulation is different, the 

 lobes being much broader, and the divisions between them 

 appearing, on the contrary, less deep." 



The inaccuracies in Lindley and Button's figure, to Avhich 

 I have previously alluded, are sufficient to justify Stur in 

 describing his plant as a new species. 



In the second part of his " Culm-Flora," the author removes 



this fern from Sphenopteris, and places it in his new genus, 



Oalymmotheca, the chief character of which is the many- 



valved sporangium — one of his species {Calymmotheca minor) 



in fact being, as already pointed out by Mr C. W. Peach, 



probably a small specimen of Staphi/lopteris Peachii, Balfour.* 



* Peach, "Ou Fossil Plants from the Calciferous Sandstone around Edin- 

 burgh" (Trans. Bot. See, vol. xiii., 1877). 



