378 



BENNETTITALBS 



[CH. 



steles similar to those in Gycas occasionally occur (fig. 511). The 

 large pith consists of parenchyma and secretory canals, and 

 internal periderm^ may be present; no medullary bundles have 

 been discovered. 



Rg. 512. Gycadeoidea ingens. Transverse section of a, young frond, above the 

 tip of the rachis, embedded in ramenta. The rachis is situated on the upper 

 side of the two ranks of pinnae. The arrow points towards the axis of the 

 stem. (After Wieland; x 4.) 



The correlation of the numerous fronds^ preserved in Meso- 



zoic strata with their parent-stems is seldom possible. It is 



known that leaves of the Zamites type were borne on stems 



(Bucklandia) agreeing with Cycadeoidea in certain features but 



^ Capelhni and Solms-Laubach (92) PI. v. fig. 2. ^ ggg Chapter xxxix. 



