38 



GRASSES OF IOWA. 



Fig. 29. Cross-section leaf of maize, ep. outer epidermis, cross-section of stoma to 

 the left; p, soft bast or phloem and companion cells; cps, chlorophyll-bearing paren- 

 chyma; d, duct; a, ringed vessel; is., intercellular space; ss, st, stereome; 'Up, Inner epi- 

 dermis. (Oombs.) 



