CORTICIUM. 119 



the substratum ; in a few species of high development the 

 extreme margin is free and sometimes more or less upraised. 

 The hymenium is perfectly glabrous and waxy, owing to the 

 entire absence of projecting cystidia, which give it a velvety 

 or minutely hispid appearance in the genera Peniophora and 

 Hymenochaete. When dry the hymenium is often cracked, 

 owing to contraction. The nodulose or uneven appearance 

 of the hymenium in some species is mainly due to having 

 grown on an uneven surface, as bark, &c. 



* Margin determinate, free. 



Corticium salicinum. Fr. (figs. 4, 5, p. 94.) 

 Coriaceous, soft, rigid when dry, fixed by the centre, 

 margin raised all round ; hymenium blood-red ; whitish and 

 villous below; spores cylindric-oblong, 14-16 x 5-6 p.. 



Corticium salicinum, Fries, Hym. Eur., p. 657 ; Stev., Fung., 

 p. 647 ; Mass., Mon. Theleph., p. 118, pi. vi. f. 1. 



On willow, poplar, &c. When young resembling a Peziza, 

 often becoming effused for 1 in. or more, margin always up- 

 turned. 



Corticium evolvens. Fr. 



Patches marginate, often effuso-reflexed, soft," whitish 

 and tomentose below; hymenium subrugose, pale brown 

 then ochraceous or whitish, cracked when dry ; spores el- 

 liptical, 10-12 X 5 p.. 



Corticium evolvens, Fries, Hym. Eur., p. 646 ; Mass., Mon. 

 Thel., p. 118, pi. vi. f. 4. 



On bark, especially of rosaceous trees. Often commencing 

 as detached minute round patches, which sometimes assume 

 a saucer-like form and remain solitary; more frequently 

 several become confluent and form irregular patches, with 

 the margin more or less upraised and fibrillose below ; hy- 

 menium dirty ochraceous, sometimes with a lilac tinge, 

 cracked when dry, and showing the fibrillose subiculum. 



Corticium porosum. B. & Curt. 



Often effused for several inches, margin sometimes deter- 

 minate and slightly raised, at others almost indeterminate ; 

 hymenium when well developed, waxy, even, pallid, with 



