PALEOBOTANY BERRY, 



340 



sequently been made the basis for a new genus, Pseudocycas, 

 although nothing is known of the plants which bore these anomalous 

 fronds. 



A frond genus that deserYes mention is Podozamites, to which a 

 very large number of often detached pinnules have been referred, 

 some of which are with difficulty distinguished from the conifero- 

 phyte genera Nageiopsis, Araucaria, etc. These are widespread and 

 more or less abundant from the Triassic to the Upper Cretaceous. 

 In the more perfect specimens Podozamites shows a slender rachis, 

 with somewhat irregularly spaced parallel veined lanceolate pin- 

 nules, often deciduous. Podozamites may well be composite. In 



Fig. 19. — Restoration of the Jurassic Williamsoniella (after Thomas), 

 a, vertical section of flower, X i- b, microsporophyll from side, X 1: c, same in transverse section. 



certain species the pinnules appear to be borne on definite short 

 shoots, and the associated fructifications (Cycadocarpidium) con- 

 sist of loose cones of sporophylls, much like the vegetative leaves, 

 and bearing proximad, two ovules with pointed wing-like appendages. 

 Podozamites in some of its forms may thus constitute a point of con- 

 tact between the cycadophytes and coniferophytes, or it may really 

 belong with the latter phylum and have no eycadean relationship. 

 The Cycadales have tuberous or columnar, sometimes subterranean, 

 sparingly or not at all branched stems, covered with persistent leaf 

 bases, bearing a crown of large compound leaves and apparently ter- 

 minal (truly lateral), dioecious strobilae. The cortex is thick, the 



