118 SPHENOZAMITES. 



base that forms a generic character of the typical Oto%amites, 

 Schimper also adopts Sphenommites as a generic name, but 

 correctly points out that Otozamites Beani of Lindley & Hutton, 

 which Brongniart gave as the type of Sphenozamites, is a true 

 Otozamites. Saporta defines the genus as follows : — 



"Frondes plerumque rachi valida tereti instructse pinnatse, 

 pinnae vel foUola latiores majusculse basi plus minusve angustata 

 subpedicellatae sequilaterales cartilagineocinctBe integrse aut apic& 

 sinuatae dentatseque spinosse, racheos lateribus ordine altemo- 

 insertoB nee unquam basibus inter se connexis racheos superflciem 

 tegentes, nervulis e loco insertionis radiantibus numerosis dichotome 

 pluries divisis." ' 



Among recent Cycads we find a similar form of pinna in species 

 of Eneephalartos and Zamia, e.g., Z. Skinneri, Z. integrifolia, 

 Z. murieata. 



Fronds conforming to the Sphenozamites pattern occur in Lower 

 Permian rocks,'"' and extend through the Jurassic system. It is a 

 convenience to adopt this generic name for fronds bearing pinnae 

 having a comparatively broad and short, more or less wedge-shaped 

 lamina; the distinction between certain forms of Otozamites and 

 Sphenozamites is often very slight, and probably does not constitute 

 a generic difference in the sense in which genera are defined among 

 existing plants. Sphenozamites, like Otozamites and numerous 

 other genera, is used in a provisional and artificial sense as 

 denoting certain characteristic features in the shape of the leaflets, 

 and not in the sense of generic designations based on characters of 

 primary taxonomic importance. In the Wealden Flora, vol. ii., 

 I described a plant under the name of Withamia, which possesses 

 broad pinnae or leaves very similar to those of Sphenozamites, but 

 distinguished by the presence of strong recurved hooks situated 

 immediately below each leaf -like appendage. Professor ZeiUer" 

 afterwards substituted the generic name Sewardia for Withamia, as- 

 I had overlooked the fact that the latter term had previously been 

 used by linger. 



' Saporta (75), p. 181. 



2 ZeiUer (00), p. 232 ; Eenault (81). 



' ZeUler (00). 



