590 CYOADOPHYTAN FRONDS [CH. 



but not along a line parallel to the long axis of the rachis as in 

 Zamites, and partially embracing it: the edge of the lamina is 

 finely denticulate; veins slightly divergent and occasionally 

 branched. The leaflets are narrow and more acute than those 

 of Noeggerathia and Sphenozamites Rochei Ken. Plagiozamites is 

 recorded from the Stephanian of Commentry, the Coal Measures 

 of Manchuria^, and the Lower Permian of the Vosges. Renault 

 described six species of Zamites from Commentry all, except 

 Z. carbonarius, based on detached pinnae. The type-specimen 

 of Z. carbonarius consists of a piece of stout rachis bearing ovate 

 acute pinnae, 2-2 x 1 cm. Potonie^, who refers a piece of pinnate 

 frond from the Permian of Thuringia to Z. carbonarius, includes 

 the other species of Renault under that name. Whether or not 

 the differences in the venation and form of the pinnae are of 

 specific significance cannot be definitely settled without better 

 material, but the important point is that these Permo-Carboni- 

 ferous fronds are sufficiently distinct from Zamites to be placed 

 in a separate genus. Plagiozamites carbonarius is recorded also 

 by Zalessky* from the Permian of Manchuria though the examples 

 figured do not afiord satisfactory evidence of the mode of insertion 

 of the segments on the rachis. P. Planchardi has recently been 

 recorded from the Coal Measures of Maryland; the discovery is 

 interesting both on phytogeographical grounds and as the first 

 satisfactory record of a Palaeozoic Cycadophyte from North 

 America*. 



Cycadorachis. Saporta. 



The employment of this generic name may serve a useful 

 purpose if used for specimens, whether preserved as petrifactions 

 or impressions, believed to be portions of Cycadean frond-axes, 

 but which in the absence of pinnae cannot be assigned to one of 

 the recognised genera of fronds. Saporta^ describes two species 

 from Blimmeridgian beds in France, Cycadorachis abscissa and 

 C. armata : the first may be the winged base of a Cycadean petiole, 

 but it agrees equally well with the broad base of an Osmundaceous 



1 Zaleasky (Oai!) p. 401, fig. 13. 



2 Potonie (93) A. p. 210, PI. xxix. fig. 5. 



= Zalessky (05^) p. 403, figs. 14, 15. * Bassler (16). 



' Saporta (75) A. p. 193, PI. 114, fig. 3j PI. 117, fig. 1. 



