264 FOUNDATIONS OF BOTANY 
applied to the cover-glass, rupture the perithecia by gentle grinding 
between the cover and slide. Note the number and form of the 
spore-sacs (asci) expelled from each of several perithecia. Examine 
under a power of about 200 diam- 
eters and count the number of spores 
in the asci. Gentle pressure may 
make them more distinctly visible. 
Make drawings to illustrate the 
structural characters observed. 
cap 
THE STUDY OF AGARICUS 
316. Occurrence. — The common 
mushroom, Agaricus campestris, 
grows in open fields and pastures 
in the United States and Europe. 
It is the mushroom most extensively 
cultivated for market, and if not 
found in the field it may be raised 
from “spawn” (mycelium), put up 
in the shape of bricks, and sold by 
seedsmen in the large cities. Those 
who make a specialty of selling it 
furnish directions for culture free. 
A moderately warm cellar or base- 
ment makes an excellent winter 
garden for mushrooms. 
317. Structure of Mycelium. — 
% Examine some of the spawn, or 
Fig, 194. — A Mushroom (Agaricus 2 : oils 
sietloun), mycelium, with the magnifying glass 
my, mycelium; c, c', ce”, young andthe low power of the microscope, 
“buttons” ; st, stipe or stalk; 7, and with a power of 200 diameters 
ring; g, gills. : A ee eee 
or more examine the individual 
hyphz which compose it. Are the hyphe united in cord-like strands 
or otherwise, or are they entirely separate? Look for cross-partitions 
in the hyphe. Is there any peculiar structure to be found at these 
places? Are the cross-partitions near together or widely separated? 
