148 



THE LIVING CYCADS 



in all cycads with terminal cones. In Macrozamia and 

 Encephalartos the cone comes from the axil of a leaf, and 



the original axis persists 

 throughout the life of the 

 plant, as in the female 

 plant of Cycas. 



The cone of Dioon 

 spinulosum is more com- 

 pact, the tips of the 

 sporophylls being closely 

 appressed; but the sporo- 

 phylls still show very 

 clearly their foliar 

 character. 



In Macrozamia the 

 female cone has reached 

 the maximum of compact- 

 ness, but the midrib of 

 the sporophyll is pro- 

 longed into a spine which 

 at once identifies the 

 genus (Fig. 83). 



Beyond this the only 

 advance is the ehmination 

 of even the spines which 

 represent the midrib or its 

 lateral leaflets. In Zamia, 

 not only has the cone 

 reached the maximum of 

 compactness, but the 

 ^ „ ,, . ,,. ,.. sporophylls bear so little 



Fig. 83. — Macrozamia Miqnelii: j. ir ^ 



female cone. resemblance to foliage 



