DESCRIPTIVE CATALOG 
UREDINESA, Dz Bary. 
Parasitic plants of minute size, growing in the tissues of 
living phenogams, or, in a few cases, of living vascular cryp- 
togams; mycelium articulated, variously branched, penetrating 
or growing between the cells of the host; spores usually pro- 
duced by constriction, singly or in chains, from the ends of 
fertile hyphe (mycelium branches), formed beneath, rarely 
within the cells of, the epidermis, which is ultimately ruptured; 
spore or fruit forms of different kinds, viz: ecidium and spermo- 
gonium, uredo and teleutoforms. 
The Uredines are parasites, and affect a very large number 
of the species of the higher plants, being found most often up- 
on the leaves, but also in some instances upon the stems and 
parts of the flower or fruit. The roots alone are free from 
their intrusion, and these probably because protected by the 
soil. ; 
The most remarkable thing concerning the Uredinee is 
their peculiar alternations of fruit forms— dimorphism,” 
* polymorphism,” or ‘ pleomorphism.” The teleutospores, the 
last in the series, and usually the only ones surviving over win- 
ter, upon germination emit a slender tube called the promyce- 
lium. This is never very long or complex in structure, but 
may be with or without septa, simple or branched. It produces 
at once, on minute stalks (sterigmata), one to several thin- 
walled, more or less globular bodies, rich in protoplasm, and 
known as sporidia. These in turn soon germinate by sending 
out a little tube, which, upon the proper host, penetrates the 
tissues and forms the mycelium or vegetative structure of the 
parasitic plant. Then follow in order, as products of the my- 
celium, the fruit forms known as spermogonium, ecidium, uredo, 
and teleutospore. The two first are usually produced simul- 
