402 THE FUNGI WHICH CAUSE PLANT DISEASE 



regarded as actually injurious. If more questionable cases were 

 to be included the number would be increased several fold. 



Key to Families of Agaiicales 



Basidia loosely aggregated on a mold-like 

 or arachnoid base, formed from loose 



floccose hyphae 1. Hypochnacese, p. 402. 



Basidia closely aggregated, forming a com- 

 pact layer 

 Hymenium smooth 

 Sporocarp effused, resupinate or rarely 



pileate, usually not fleshy 2. Thelephoracese, p. 405. 



Sporocarp clavate, the upper portion 



only sporogenous, usuaUy fleshy. . 3. Clavariacese, p. 412. 

 Hymenium variously folded or pitted 

 Hymenium with teeth, tubercles or 

 tooth-like plates which are sporo- 

 genous 4. Hydnacese, p. 413. 



Hjnnenium lining pores 

 Pores not easily separating from the 

 pileus, which is commonly 



leathery, corky or punky 5. Polyporacese, p. 416. 



Pores readily separating from the 



pileus which is fleshy 6. Boletaces, p. 440. 



Hymenium covering the surface of 



radiating plates 7. Agaricacese, p. 442. 



Hypochnaceae 



Sporophore poorly developed and often indefinite, of loosely 

 woven floccose hyphae; the basidia clavate, loosely aggregated 

 into an ill-defined hymenium. 



In the simplicity of the sporogenous structures the members 

 of the group approach the Hyphomycetes from which they are 

 separated only by their sporophores which are of the nature of 

 basidia rather than of ordinary conidiophores. 



A small family of some half dozen genera and sixty species. 



