92 



MORPHOLOGY OF GYMNOSPERMS 



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

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



•T J tr •'** '*- ^^i^^^^*^ 



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

 the trunk is i . 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 



