92 



MORPHOLOGY OF GYMNOSPERMS 



r and from the Cordaitales by the unbranched stem, with a terminal 

 rosette of comparatively few, large, branched leaves, which gives the 



Fig. 70. — Dioon edule: ovulate plant on rocky hillside at Chavarrillo, Mexico; 

 the trunk is 1.5 m. high, and shows the armor of leaf bases throughout its entire 

 length. — After Chamberlain (46). 



•/ columnar forms the habit of the tree ferns or palms (fig. 70). The 

 definitely organized strobili readily separate the cycads from the 



