284 
PLANT STUDIES 
nected together, so that a mycelium bearing uredospores is 
called a Uredo, one bearing teleutospores a Puccinia, and 
one bearing secidia an ^Ecidiuin ; but what forms of Uredo, 
Puccinia, and ^cidium belong together in the same life 
cycle is very difficult to discover. 
Another life cycle which has been discovered is in con- 
nection with the "cedar apples" which appear on red 
cedar (Fig. 254). In the spring these diseased growths be- 
come conspicuous, especially after a rain, when the jelly- 
like masses containing the orange-colored spores swell. 
This corresponds to the phase which produces rust in 
wheat. On the leaves of apple trees, wild crab, hawthorn, 
etc., the aecidium stage of the same parasite develops. 
4. BASIDIOMYCETES (Basidium-Fungi). 
189. General characters. This group includes the mush- 
rooms, toadstools, and puffballs. They are not destructive 
parasites, as are many 
forms in the preceding 
groups, but mostly harm- 
less and often useful sap- 
rophytes. They must 
also be regarded as the 
most highly organized of 
V pp^ the Fungi. The popular 
distinction between toad- 
stools and mushrooms is 
not borne out by botan- 
ical characters, toadstool 
and mushroom being the 
same thing botanically, 
and forming one group, 
puffballs forming an- 
other. 
As in ^Ecidiomycetes, 
FIG. 255. The common edible mushroom, 
Agaricus campestris. After GIBSON. HO SCXUal prOCCSS has 
