Chapter XI. 



Fungi. Kinds of Fungi. Basidium-bearing Fungi. 



M 



The stalked or basidium-bearing fungi (Basidiomycetes). 

 This is the third of the three great groups of fungi. The 

 members of this group do not, as the sac fungi, bear their 

 spores in sacs, but form them upon more or less definite stalks, 

 which occur with some degree of regularity upon special por- 

 tions, usually the ends, of the fungus threads. From these 

 stalks the spores are pinched off just as are many accessory 

 spores in sac fungi. They are not formed internally, as the 

 spores are in sacs, but are externally formed in the pinching- 

 off process. The stalks usually occur in fours at the end of 

 the thread though they may be fewer or greater in number 

 and may arise laterally on the stalk-bearing threads. The cell 

 or cells of the thread which bear the stalks are known as the 

 basidium. In the lower group of the stalked fungi, the basidi- 

 um is composed of a number of cells each of which bears a 

 stalk with its spore as in rusts and smuts, "Jews' ear," trem- 

 bling and weeping fungi. In the higher forms, comprising the 

 other groups, all of the stalks arise from a single undivided 

 cell. The basidium may arise directly from a spore (winter 

 spore) as in the rusts and smuts. In these forms, of course, 

 they are often found singly, but when the winter spores are 

 formed in crust-forming clusters they are produced in a more 

 or less dense mass. In all other stalked fungi the basidia are 

 borne on or in some fruiting body or on the surface of mold- 

 like growths. The former is by far the more common form, 

 as in the gelatinous fungi, in the mushrooms and all of their 

 aUies and the great alliance of puff balls, birds'-nest and car- 

 rion fungi. When borne at the surface of a fruiting body the 

 basidia usually stand closely together side by side and perpen- 

 dicular to the surface of the fruiting body, with occasional 

 sterile threads between them, thus constituting a palisade, cov- 



