AGARICALES 103 



become reduced to mere tubercles or irregular ridges. The 

 genera may be distinguished by the following synopsis : 



1. Plant consisting of teeth only with no basal membrane or context. 



MUCRONELLA 



Plant consisting of teeth attached to a basal membrane or to a pileus 2 



2. Hymenium covering needle-like spines. 3 

 Hymenium covering lamella-like teeth. 4 

 Resupinate, the hymenium with warts, M-rinkles or simple bristles. 5 



3. Spines irregular, thick and blunt. Radulum 

 Spines awl-shaped, usually regular. Hydnum 



4. Context coriaceous, pileate or resupinate ; epixylous. Irpex 

 Context fleshy or membranous, pileate ; terrestrial. Sistotrema 



5. Ilymenial surface with simple bristles. Pycnodon.^ 



Hymenial surface with low crested wrinkles. PiiLEBiA. 



Hymenial surface warty. 6. 



6. Warts hemispheric, smooth. Grandinia. 

 Warts crested, papillose. Odontium. 



Of the above genera Hydmim is the only large genus and is 

 composed of numerous groups of diverse habit. Some of these 

 are so distinct that they have been set apart as genera, some of 

 which will doubtless be regarded valid. Several of the species of 

 Hydmcm are edible. Among them are the following : 



1. Species loitJi a central stem. 



H. repandiiJii has a yellowish or slightly reddish pileus with an 

 irregular margin, is compact but brittle, with a dry, whitish con- 

 text; the pileus is one to four inches wide and the stem is one to 

 three inches in length. 



H. i/nbricatinu is a larger species, often six inches or more in 

 diameter with a brownish pileus covered more or less closely with 

 irregular scales of a darker color ; the centre is sometimes de- 

 pressed so that the fungus appears funnel-shaped. 



2. Species growijig in branched masses with 110 distinct pileus. 

 H. coralloides is a pure white fungus of coral-like character, 



often composed of many spreading and often interlacing branches 

 covered with short spines scarcely a third of an inch in length. 

 It is a beautiful species most common on trunks of beech wood. 



*This is the Kneiffia of Fries, a name which is preoccupied. Cf. Bull. 

 Torrey Bot. Club, 25: 630, 631. 1898. 



