156 Illinois State Laboratory of Natural History. 
III. Spores at maturity in a dense, waxy or crust-like stratum, 
not separating from each other. 
A. Spores one-celled, less commonly several-celled, and 
then the septa almost never horizontal, mostly dull 
reddish brown. 
1. Spores one-celled, oblong, united in an erect (often 
curved ) cylindrical column...... CRONARTIUM. 
2. Spores one or more celled, septa, when present, 
mostly vertical or oblique, united in a flat or 
convex stratum..............-. MELAMPSORA. 
B. Spores several-celled, septa horizontal, mostly reddish- 
orange. 
1. Spore cells short (not longer than wide), united 
in a flat waxy mass, cell rows simple. 
CoLEOSPORIUM. 
2. Spore cells oblong or cylindrical, in simple or 
branched vertical rows, not waxy . CHRYSOMYXA. 
UROMYCES Link. 
Teleutospores one-celled, brown, produced singly on per- 
manent pedicels, usually longer than the spore, arising from a 
compact layer of small irregularly shaped cells beneath the epi- 
dermis, which is finally ruptured, exposing the more or less 
powdery mass. 
Like most of the genera of Uiedinew the biological 
development of the Uroimyces is very complex, and in the dif- 
ferent species variously diversified. All the spore-forms exist 
on the same or different hosts, or any one, or even all but one 
(the teleutospore) may be wanting. In most cases the teleuto- 
spore germinates only after a considerable period of rest, but 
in a few species exceptions to this occur, and there are also 
exceptions in regard to the permanence of the pedicels. When 
the spores readily fall from the stalks, they can be distin- 
guished from stalked uredospores by the different appearance — 
usually smooth instead of being roughened with minute and 
mostly sharp-pointed prominences — or by the tardy germina- 
tion when ripe. Puzzling forms occur, in which some of the 
