PRINCIPAL GROUPS OF PLANTS. 59 



A, B, C). In some cases the under surface is composed of 

 a series of narrow, radiating, knife-like plates, or gills, as in 

 the common edible mushroom Agaricus. On the surface of 

 the gills the basidia or spore-bearing organs arise. The basidia 

 are somewhat swollen terminal cells of the closely arranged hyphae 

 composing the gills, which bear a group of spores on short stalks 

 (Fig. 33, C). Both the basidia and spores (basidio-spores) are 

 of a characteristic size and number for the different species. 



Several types of Basidiomycetes are usually recognized, de- 

 pending on the manner in which the spores are borne. 



i. The Gill Fungi (Agaricaceae), in which the spores are 

 borne on plates or gills which radiate from the stem to the edge 

 of the cap. 



2. The Pore Fungi (Polyporaceae), in which the spores are 

 borne in tubes or pits opening by pores rather than on gills. 



3. The Coral Fungi (Clavariaceae), in which the Fungi are 

 coral-like or leaf-like, the surface of the cap or its branches being 

 smooth. 



4. The Leather Fungi (Thelephoraceae), in which the spore- 

 bearing surface is smooth or slightly wrinkled. The texture is 

 usually leathery or papery. 



5. The Jelly Fungi (Tremellaceae), in which the fruiting sur- 

 face is smooth and the cap is more or less jelly-like when wet. 



6. The Puff Balls (Lycoperdaceae), in which the cap is a 

 closed ball which breaks open at maturity to release the enclosed 

 spores. 



7. The Carrion Fungi or Stink-horn Fungi (Phallaceae) re- 

 semble the puffballs when young, but are ruptured longitudinally, 

 the spores thereby being exposed on the top as a gelatinous mass. 



Of these seven groups the Gill Fungi are the commonest, and 

 one or two types will be considered, namely, the common edible 

 mushroom and two of the poisonous group, Amanita. 



Edible Fungi. Agaricus campestris (common mushroom) 

 (Figs. 33 and 34) is practically the only edible species cultivated 

 in this country. The plant grows wild in open grassy fields dur- 

 ing August and September. It is not found in the mountains to 

 any extent, and is never found in the woods or on trees or fallen 

 trunks. The color of the stipe and the upper surface of the 



