8 



THE STEM. 



The young stem of a grass when cut across will be found 

 to contain numerous threads {fihro-vascular lundles) scattered 

 from the center to the circumference. An epidermis covers the 

 whole. Ih many instances,, as the stem enlarges, the inside is 

 ruptured and a hollow is formed. 



Neither roots nor leaves could last long without each other. 



The slender branches of the 

 jmnicles of liporobolus hetero- 

 Iej)is, a grass common on the 

 prairies of the west, are cov- 

 ered in places with a gummy 

 excretion which entraps small 

 insects. Dr. Bessey in the 

 American Naturalist, }). 420, 

 1884, suggests that they may 

 serve the same purpose as the 

 similar sticky belts in Silene 

 or catch-fly, viz. : to entra]) 

 crawling insects and j)revent 

 them from reaching the flow- 

 ers which they are incapable 

 of fertilizing. 



The naked j^ortions of the 

 internodes of Tragus race- 

 mosus var. occidentalis, a wild 

 grass of Arizona, are furnished 

 with a sticky substance. The 

 specimens examined are cov- 

 ered with many particles of 

 sand and dust. 



The main uses of the stem 

 appear to be to convey the sap 

 to or from the leaves, to sup- 



FiO. 6.— Represents a young stem of Festttca ,^„,.f +i,„ loQ-iroc. onrl ov+o-nrl 

 fi it branches at the base.-^(Hackel.) PO^ t tJie leaVCb anCl extena 



