CHAPTER XXXIX. 



CYCADOPHYTAN FRONDS. 



OCCASIONAL reference is made to Cycadean fronds in the 

 account of flowers and stems but it is seldom that genera or 

 species founded on leaves can be definitely correlated with parti- 

 cular types of reproductive organs or stems. As in the case of 

 Ferns and Pteridosperms so also with detached leaves believed 

 to be Cycadean, a large number of generic names have been 

 employed for impressions which afford no information with 

 regard to anatomical characters except, in some of the more 

 favourably preserved specimens, a few facts as to the epidermal 

 cells. Though association often suggests original connexion it is 

 inadvisable except in well established cases to extend to fronds 

 generic terms based on reproductive shoots. The designation 

 Zamites has long been used for fronds that are clearly not closely 

 related to recent species of Zamia, and were it not an old estab- 

 lished genus the significance of which is not likely to be misunder- 

 stood, it would be wiser to substitute for it some name implying 

 no affinity with any existing type. On the other hand the 

 employment by some authors of such generic names as Encepha- 

 lartos and Ceratozamia is not warranted by the evidence furnished 

 by the imperfect material. Prof. Newberry 1 described as Encepha- 

 lartost denticulatus a piece of a frond from Rhaetic beds in Hon- 

 duras characterised by lanceolate pinnae (30 x 6mm.) gradually 

 narrowed towards the acute apex and abruptly contracted at 

 the base: the method of attachment of the pinnae appears to 

 agree with that in the genus Zamites. In this case there is no 



1 Newberry (88) p. 346, PI. vm. fig. 5. 



