202 PUNGUS-PLOEA. 



thin membranaceous film that here and there produces 

 clusters of large, irregular pores averaging about ^ mm. 

 across. 



Forming a thin, white, or slightly rufescent, byssoid, 

 broadly effused, close membrane, here and there traversed by 

 rooting ribs. (Fries.) 



Poria callosa. , Fr. 



Broadly effused, white, equal, tough, separable like a 

 sheet of leather, flesh thick, firm, but not rigid, 1-2 lines 

 thick, everywhere covered with round, equal, quite entire 

 pores that form a firm stratum, spores obliquely elliptical, 

 6 X 3-5 /t. 



Polyporus callosus. Fries, Syst. Myc. i. p. 381 ; Stev., Brit 

 Fung., p. 217. 



On rotten wood. Eeadily known by the thick, leather- 

 like flesh, and by separating readily from the substratum. 



Poria mucida. Fr. 



White, then pallid, rather thick, soft, subimmersed, margin 

 indeterminate, byssoid, pores medium-sized, unequal, torn, 

 seated on the flesh formed by the mycelium. 



Polyporus mucidus. Fries, Syst. Myc. i. p. 382 ; Stev., 

 Brit. Fung., p. 217. 



On rotten fir wood. Forming patches 5-6 in. or more 

 long, ^ in. or more thick. Varies, softer or firmer according 

 to the position, but is moderately persistent, generally moist, 

 much thicker than P. mollusca. Tubes 1-3 mm. long, pores 

 ^|— ^ mm. across. 



Poria hybrida. B. & Br. 



White, mycelium forming rather thick, felt-like patches 

 or branched, creeping strands ; pores long, minute, slender, 

 in scattered patches, not forming a continuous hymenium ; 

 spores elliptic-oblong, colourless, 4 X 2 /i. 



Polyporus hyhridus. Berk. & Broome, in Berk., Outl., 

 p. xviii; Stev., Fung., p. 221. 



On oak wood. Causing the dry-rot of oak ships. Sup- 

 posed by Fries to be a morbid form of some species (perhaps 

 P. destructor), its peculiarities caused by the abnormal con- 

 dition under which it occurs. Pores about ^ mm. diameter, 

 2-4 mm. long. 



