7o 



BOTANICAL GAZETTE 



[JULY 



does not appear at first. There is one protoxylem point on either 

 side with the phloem between, which develops directly into the 

 parallel-banded types (figs. 12, 13). These parallel bands of xylem 

 may develop into crescent-shaped xylem masses. The crescent- 

 shaped xylem is a high development of the parallel-banded type of 

 stele, formed, as in L. carinatum, by the growth of xylem around one 

 end of the phloem (fig. 9). The mature stem and the vegetative 



Fig. 11. — L. varium: section in the same series as fig. 10, showing the develop- 

 ment of the parallel-banded type from the radial; /, leaf trace; px, protoxylem; p, 

 phloem; X500. 



stem 

 ment 



material 



bearing, but the vegetative portions show the radial arrangement 

 (fig- *$)• Tll e type of the stele in all cases in these species, as in 

 L. carinatum, is determined bv the growth of the metaxvlem. 



stems, clay mo 



made of the xvlem 



