STEREUM. 129 



intermediate layer ; basidia tetrasporous ; spores continuous, 

 hyaline or coloured. 



Stereum, Persoon, Obs. Myc., p. 35 ; Mass., Mon. Thel. r 

 p. 158. 



The leading characters of the present genus are the smooth, 

 even hymenium, and the velvety or strigose pileus. In 

 Peniophora and Hymenochaete the habit is the same as those 

 of resupinate or reflexed species of the present genus, but in 

 both the hymenium is minutely velvety or setulose. In the 

 present genus there is an unbroken sequence from the 

 Mesopod or central-stemmed type, with a more or less funnel- 

 shaped pileus and inferior hymenium, through the lateral- 

 stemmed or flabelliform, to the effused stage with a more or 

 less developed free margin, or several free margins springing 

 from the effused and adnate portion in a superposed, imbricate 

 or dimidiate manner. This last leads by degrees to the 

 lowest type, where the whole fungus is closely adnate to the 

 substratum by its under surface, and consequently, having 

 the hymenium uppermost, thus closely agreeing with the 

 normal condition in the genus Corticium, but distinguished 

 by the presence of a layer of closely compacted hyphae, 

 which directly gives origin to the elements of the hymenial 

 layer; from the underside of this compact layer a loose felted 

 layer of hyphae rests on and penetrates the substratum. In 

 Corticium no such layer exists. Again, in Stereum, as a rule 

 the hymenium does not become cracked when dry, as is fre- 

 quently the case in Corticium, and in the resupinate forms- 

 the margin is rarely indeterminate, but usually more or les& 

 free and strigose. 



* Pileus infundibuliform, stem central. 



Stereum Sowerbei. Massee. (fig. 13, p. 97.) 



Snow-white, pileus infundibuliform, |~1 in. across, rather 

 rough with projecting points, but not velvety, margin vari- 

 ously incised ; hymenium smooth ; spores elliptical, 5 X 3 p.. 



Stereum Sowerbei, Mass., Mon. Thel., p. 164. 



Thelepliora Sowerbei, Berk., Outl., p. 206. 



Eh-ella pannosa, Sow., Fung., t. 155. 



On the ground. A very beautiful species, snow-white, 

 tinged with pale buff when old, and of a waxy appearance 



VOL. I. K 



