CRYPTOGAMS 319 
only the dark teleutospores are produced. These remain on 
the culms in the stubble fields over winter, ready to begin 
the work of reproduction in spring. For this reason the 
teleutos are popularly known as “ winter spores ”’ in contra- 
distinction to the uredos, or ‘‘ summer spores,”’ whose activity 
is confined to the warm months. 
It was formerly supposed that black rust was caused by a 
different fungus from that producing red rust, and to it the 
name Puccinia was given. This has been 
retained as a general designation for all fungi 
undergoing these two phases, and the par- 
ticular form of fungus that we are now con- 
sidering is known in all its stages as Puccinia 
graminis. 
361. The nonparasitic stage.— The for- 
mation of teleutospores completes that por- 
tion of the life history of the fungus during 
which it is parasitic on wheat and grasses of 
different kinds. In spring they begin to 
germinate on the ground, each cell producing 
a small filament, from which arise in turn 
several small branches. Upon the tip of 
2 : Fic. 454, — Teleu- 
each of these branches is developed a tiny tospore germinating 
and forming sporidia, 
sporelike body called a sporidium (Fig. 454), 55. (Prom Cour. 
which continues the generation of the rust 7's “Plant Struc- 
fungus through the next stage of its exist- Ere 
ence. The filament which bears these sporidia is not para- 
sitic, but when the sporidia ripen and the spores contained 
in them are scattered by the wind, there begins a second 
parasitic phase, which forms the most curious part of this 
strange life history. 
362. The ecidium.— Examine next the under side of 
some barberry leaves (or comfrey, etc., if orange leaf-rust 
is used) for clusters of small whitish bodies that appear 
under the lens like little white corollas with yellow anthers 
in the center. Examine a section of one of these under the 
