TAXONOMY 
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Sub-class A. — Protobasidiomycetes 
(Basidium four-celled, each cell bearing a spore) 
Order 1.- — Ustilaginales, the smuts. Destructive parasites which 
attack the flowers of various cereals, occasionally other parts of these 
plants. Example: Ustilago Maydis, the corn smut. The basidio- 
spores in this group are borne on promycelia. 
Fig. 96. — Germination of the chlamydospores of corn smut ( Ustilago zece)\ 1, 
Various stages in germination from corn 3 days after being placed in water; 2, 
spores germinated in contact with air; 3, several days after spores were placed in 
yio per cent, acetic acid, formation of infection threads, a, Spores; b, promy- 
celia; c, basidiospores; d, infection threads; e, detached pieces of mycelia. ( After 
Bull. 57, Univ. III. Agric. Exper. Slat., March, 1900.) 
Ustilago Maydis (Ustilago Zeae) (Corn Smut). — Corn smut is a 
destructive parasite which for a long time was supposed to be con- 
fined to the Indian Corn, but which now is known to occur on 
Mexican Grass. It is the only smut useful in medicine. The 
