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. 



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 

 mvcelium, with the magnifying glass 

 and the low power of the microscope, 

 and with a power of 200 diameters 

 or more examine the individual 



hyphee which compose it. Are the hyphae united in cord-like strands 

 or otherwise, or are they entirely separate ? Look for cross-partitions 

 in the hyphae. Is there any peculiar structure to be found at these 

 places ? Are the cross-partitions near together or widely separated ? 



FlG. 194. A Mushroom (Agaricus 



melleus). 

 my, mycelium ; c, c', c", young 



"buttons" ; st, stipe or stalk ; r, 



ring ; g, gills. 



