THE BASIDIUM FUNGI (BASIDIOMYCETES) 249 



FIG. 203. Gills of a 

 toadstool 



On the faces of the gills 

 the spores are formed. 

 Seven and one-half times 

 natural size. After Buller 



end of the stalk (stipe) (Fig. 202). As the pileus opens, it is 



joined to the stalk beneath by means of a layer of hyphse (the 

 veil). This in some species, in breaking 

 away from the pileus, forms a ring or 

 annulus about the stalk. 



The underside of the pileus is made 

 up of plate-like growths (jjills), which 

 radiate from the point of attachment to 

 the stalk. The flat surfaces of the adja- 

 cent plates face one another (Fig. 203). 

 Some of the hyphse which compose the 

 gills grow in such a way that their tips 

 extend a little way from the surface of 

 the gill. Upon this extended tip (ba- 

 sidium) four (rarely two) branches are 

 formed, and upon the tip of each branch 

 a spore (basidiospore) is formed (Fig. 

 204). When the spores fall upon moist, 



warm, nutrient material, they produce a new mycelium. By 



cutting the pileus of a ripe toadstool from the stalk and placing 



it with the gills downward upon 



a piece of ordinary white or black 



paper, after a few hours there will 



be made a "spore print" composed 



of thousands of spores. 



237. Toadstools and mushrooms: 



different forms and habits. The type 



form just described is representa- 

 tive of the most common toadstools 



&iid mushrooms. The commonest 



Cultivated mushroom (Agaricus cam- 



pestris) has long been a well-known 



article of food. Some of the same 



type of toadstools form " fairy rings " (Figs. 205 and 206), 



which in constantly widening circles may appear in the same 



locality" year after year. The phenomenon is doubtless due 



FIG. 204. Basidia arid spores 

 of a toadstool 



Three hundred seventy times 

 natural size. After Buller 



