LIFE HISTORIES OF FUNGI 283 
buttons enlarge, a little chamber forms near the tip (Fig, 
205), and into this chamber some of the hyphae grow, form- 
ing the "gills," with their "fruiting" surface. While the 
gills are forming other hyphae form a veil, extending from 
the stipe to the edge of the pileus, and protecting the 
gills until the spores are ripe. By continued growth of 
the pileus the veil becomes ruptured, thus allowing the 
spores to escape. It has been found that the spores do 
not merely fall from the sterigmata from their own weight, 
but that they are forcibly expelled. 
Entire new mushrooms may also be obtained by growing 
pieces of a young plant on suitable nutrient media. From 
such pieces mycelium is produced which ultimately bears 
the "buttons." 
OUTLINE OF LIFE HISTORY OF MEADOW-MUSHROOM 
Spore (Basidiospore) 
4 
Mycelium 
4 
Binucleate cells 
44 
Young sporophore ("Buttons") 
1 4, . 
Mature sporophore (the "Mushroom") > 
Gills 
44 
Hymenium 
4.4 
Basidium (Nuclear fusion) 
4- } Reduction 
Sterigma 
4 
Spore (Basidiospore) 
272. Other Classes of Fleshy Fungi. In addition to 
the gill-bearing fungi (Agaricaceae) , there are many other 
families of Basidiomycetes, one bearing the fruiting sur- 
