470 



A TEXTBOOK OF BOTANY 



[CH.X 



ORDERS. HYMENOMYCETES: THE TOADSTOOL FUNGI. These 

 are the Fungi par excellence to most people. They are 

 chiefly saprophytic, having a slender-branching wide-rang- 

 ing mycelium invisible in the ground or in dead tree 

 trunks, and a prominent, typically umbrella-shaped sporo- 

 phore (toadstool) on the surface. On the under side of the 

 sporophore, and hence under protection from rain, falling 

 debris, etc., occurs a hymenium (whence the name of the 



FIG. 328. ' Typical mycelium of the Agaricineae (Amanita vernus) , 

 showing its fine structure, and origin of the sporophores. 



(Adapted from W. Hamilton Gibson, Our Edible . . . Mushrooms.) 



order), containing basidia which produce the wind-carried 

 basidiospores. The tissues of this sporophore, as of all 

 Fungi, consist only of hyphal threads, which in this case 

 are so compactly parallel or intertwined as to simulate the 

 parenchyma of higher plants. Ordinarily soft in texture 

 and sometimes collapsing in a deliquescent-gelatinous mass 

 after shedding the spores, they are often persistent and 

 hard as wood. Rarely other spores, especially conidia, are 

 formed, but for the most part the basidiospores are the 

 only reproductive bodies. No less than 10,000 species are 



