398 PHARMACEUTICAL BOTANY 
German silver. Later the cells of the hyphae lay down walls 
becoming divided into smaller cells, each of which becomes 
rounded off as a spore. This spore is known as a chlamydospore 
or brand spore. ‘The spores are at first a dark olive-green, but on 
Fic. 295.—Smut boil of Ustilago zee on ear of corn, developed from one infected 
kernel. (After Jackson, F. S., Bull. 83, Del. Coll. Agric. Exper. Stat., December, 1908.) 
maturity are dark brown. They are sub-spherical and show 
prominent but tiny spines. ‘These spores fall to the ground 
and pass the winter. In the spring each germinates into a three- 
to five-celled filament called a promycelium, from the cells of which 
