240 Plants and their Ways in South Africa 



The Cycadacese 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. Friderici Guilielmi, Lehm., which grows 



