GRASSES OF IOWA. 



19 



phragms or plates of tissue which separate the pith cavities c f 

 the internodes. " 



The function of the sclerenchyma is to give the plant firm- 

 ness and support. It is evident that strength is obtained best 



Fig. 13. Oross-sectlun bundle of maize stem, .r, xylem or wood; s, p, pr, p, "phloem 

 or soft bast; 8, p. sieve tubes; pr, p, companion celis; s«, sclerids, the mechanical ele- 

 ments; Oj ringed vessels; d, duct; par, parenchyma; ts, intereellularspace. (Oombs.) 



