240 Plants and their Ways in South Africa 



The Cycadaceae come of a very ancient lineage, for their 

 fossil forms are found in older rock formations than those of 

 any of their living Gymnosperm relatives. 



A xerophytic character of these plants is the well-developed 

 underground stem system by which vegetative reproduction 



Fig. 214. — Stangeria zeyheri. Showing the feathered venation. 



is secured. A curious feature is shown in Fig. 213. From 

 the upper portion of the tap root, roots are given off which 

 grow directly upward {apogeotropic). These contain within 

 their cortex small blue-green algae which may assist in the re- 

 spiration of the roots. 



The cones of E. Frideriri Gmlielmi, Lehm., which grows 



