THE FUNGI 259 
335. Discussion. — The wheat rust is interesting to the 
botanist on account of its singular variety of methods 
of asexual spore formation. It is also of great practi- 
cal importance, as it is a very dangerous enemy of the 
grain farmer. Comparatively rust-proof species of wheat 
are much in demand. Barberry bushes should never be 
allowed to grow in wheat-raising regions, and in many 
parts of England they have been nearly or quite exter- 
minated by farmers. Where no barberries are found the 
rust is carried from one 
wheat crop to the next by 
uredospores only. 
PSALLIOTA, ONE OF THE 
BASIDIA FUNGI 
336. Occurrence. — The 
‘common mushroom, Psal- 
liota campestris (often 
known as Agaricus campes- 
tris), grows in open fields 
and pastures in the United 
States and Europe. It is the srusbedon most extensively 
cultivated for market, and if not found in the field it may” 
be raised from “spawn” (mycelium), put up im the shape 
of bricks and sold by seedsmen in the large cities. Those 
who make a specialty of selling it furnish directions for 
culture. A moderately warm cellar or basement makes 
an excellent winter garden for mushrooms. 
There are many other gill fungi of frequent occurrence 
besides the edible mushroom. Most of them are commonly 
known as toadstools. Any of these may be collected for 
Trametes Pini, a 
Basidia Fungus. 
This species is parasitic on 
coniferous trees and does 
them much injury. 
