i6 



GYMNOSPERMS 



those of larger diameter, were adventitious and aerial. Since the 

 roots come off anywhere in the periphery, the stem could not have 

 been prostrate. Its symmetrical character and great length in pro- 



FiG. lo. — Splicnopleris hoetiighausi: photo of a leaf, showing forking of the main 

 rachis; I natural size. — After PoxoNifi. 



portion to its diameter, as well as these radially arranged roots, indi- 

 cate a climbing habit. 



The roots have a radial exarch cylinder with phloem alternating 

 with xylem rays. In the larger roots, secondary wood is developed, 

 the strands alternating with the protoxylcm points. The protoxy- 

 lem consists of spirally marked tracheids. Rootlets develop opposite 



