CHAPTER LT. 



PODOZAMITES AND NAGEIOPSIS; 

 GENERA INCERTAE SEDIS. 



PODOZAMITES Braun, and CYCADOCARPIDIUM Nathorst. 



The name Podozamites 1 was instituted for certain species pre- 

 viously included in Zamites characterised by the possession of distant 

 alternate pinnae with a contracted base and veins slightly spreading 

 in the proximal part of the lamina but for the most part approxi- 

 mately parallel. As defined by Braun Podozamites differs in no 

 very important respect from Zamites, and the latter name is retained 

 by Schenk for Z. distans Presl in preference to Podozamites applied 

 to that species by Braun. By most authors Podozamites has been 

 regarded as Cycadean, but Schenk's discovery of a specimen of 

 Podozamites 2 in the Rhaetic beds of Franconia showing a cluster 

 of small scale-leaves at the base of the axis led him to suggest a 

 possible affinity to Agathis as an alternative to the generally 

 accepted view that the appendages are leaflets or pinnae homo- 

 logous with those of a pinnate Cycadean frond. In a later paper 

 Schenk included in Podozamites some undoubted pinnate fronds 

 on which Schimper founded the genus Glossozamites 3 . Schenk 

 was, however, influenced in his preference for a Cycadean alliance 

 by the structure of the epidermal cells (fig. 812, E) which have 

 straight walls, and the same consideration weighed with Zeiller 4 

 who was strengthened in his view by the characters of the seed- 

 bearing sporophylls described by Nathorst 5 and provisionally 

 connected by him with Podozamites. Nathorst 6 described a speci- 

 men from the Rhaetic strata of Scania agreeing in the presence of 

 basal scale-leaves with that figured by Schenk, and more recently 



1 Braun (43) p. 36. 2 Schenk (67) A. PI. xxxvi. fig. 3. 



3 Ibid. (71) PL n. 4 Zeiller (03) B. p. 159. 



5 Nathorst (86) p. 91, PI. xxvi. 6 Ibid. (86) PI. xvi. fig. 10. 



