268 



PHARMACEUTICAL BOTANY 



Order 2. Uredinales, the rusts. Obligate parasites possessing 

 a septated branched mycelium which ramifies through the inter- 



FIG. 139. Smut boil of Ustilago zeoe on ear of corn, developed from one in- 

 fected kernel. (After Jackson, F. S., Bull. 83, Del. Coll. Agric. Exper. Stat., 

 December, 1908.) 



cellular-air-spaces of the host and sends haustoria into the cell 

 cavities. The different stages of their life cycle are either restricted 



