36 INTRODUCTION TO THE STUDY OF FUNGI 



Fomes cornu-oovis, but smooth, and mostly shining, often 

 laccate, as if varnished. According to Wettstein, 1 this is 

 due to the secretion of resin which oozes from peculiar 

 hyphae and flows over the surface of the pileus. The exterior 

 of the pileus exhibits deep concentrated channels, which mark 

 the annual additions at the circumference. The substance is 

 often very thick and fibrous, the fibres radiating in every direction 

 from the base. They may continue growing by the addition 

 of external zones for many years, always the oldest posteriorly. 

 From these Polystictus differs in being much thinner, and the 

 cuticle is fibrous, hairy, woolly, or strigose, and concentrically 

 zoned. The substance is dry, tough, and leathery, usually 

 flexible. In so far as these features are concerned, Stereum not 

 only resembles Polystictus in appearance, but also in texture, 

 and so does Hymenochaete ; whilst Hexagona differs more in the 

 hymenium than in anything else. These, therefore, may be 

 accepted as representing the two forms of the sessile receptacle 

 in Hymenomycetal Fungi — the woody by Fomes, to which might 

 be added Daedalea, and the coriaceous by Polystictus, and the 

 others above named. 



The next form of receptacle to be adduced is the peridium, 

 which completely encloses the reproductive organs, and may 

 also be supported on a distinct carpophore, or it may be sessile 

 on the mycelium, or invested by it, as in some subterranean 

 species. The Gastromycetes furnish this kind of receptacle, 



which is very often double, typically 

 /0ffi&- llllls, glohose, the outer coat or exoperidium 



being a continuation of the cortex 

 of the carpophore when the latter 

 exists. The internal cavity is filled 

 with the reproductive bodies, which 

 are only liberated by the rupture of 

 the coat of the peridium. The inner 

 Fig. 18.— Lycoperdon, peridium coat or endoperidium is often thin and 

 :il!!i ""''" membranaceous, and may either be 



wholly separated from the outer or adnate therewith (Fig. 18). 

 A prolongation from the carpophore sometimes protrudes into the 

 central cavity in the form of a columella. The outer coat or 

 1 Verhand. Zool. Bot. Gesell., Wien, xxxv. (1886), p. 29. 



