AGARICALES 



101 



8. Cystidia simple, unbranched. 9. 

 Cystidia branched, star-shaped. ASTEROSTROMA. 



9. Context uniform, always resupinate. PENIOPHORA. 

 (Context formed of different layers, often pileate. HYMENOCHAETE. 



Of the above genera Aleurodiscits and Michenera are small 

 genera, the former with two closely allied species often seen on 

 the bark of Ostrya where they form discrete patches ; the latter 

 genus has only a single species with us. Coniophora and espe- 

 cially Corticiuin are larger genera, and our species are poorly 

 known and many of them difficult to identify ; probably over 

 one hundred nominal species are described from the United 

 States. 



Stereum and Hymenochaete represent the common leathery or 

 woody genera growing on logs. The species of the latter genus 

 are usually brownish in color, in addition to the possession of 

 cystidia which are usually easy to discover. Stereum versicolor is 

 a common pileate species and S. frustulosum is a perennial re- 

 supinate species everywhere common on oak whose wood it 

 renders very hard and brittle. Several species of each genus are 

 common and widely distributed. One anomalous species of 

 Hymenochaete (//! agglutinans) often grows on living twigs and 

 strangles them to death. 



Thelephora is more commonly terrestrial and pileate, including 

 leathery species. While most of the species resemble Stereum in 

 shape, T. Schweinitzii is much branched and is quite frequently 

 mistaken for a Clai'aHa ; some other species are even more 

 finely laciniate ; T. Willeyi is goblet-shaped. One anomalous 

 species (T. pediccUata) grows around the living stems of young 

 trees. 



Cratercllus contains chiefly fleshy species and forms a striking 

 connecting link to the Agaricaceae through Gantharellus ; so close 

 is the connection that it is difficult in the case of certain specimens 

 to determine whether the plant belongs to one genus or the other. 

 This is only another indication that the limitation groups we are 

 here discussing are artificial rather than natural. 



Family 3. Clavariaceae. 



The more conspicuous members of this family are club-like 

 and simple or form fleshy coral-like masses of various shades of 



