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Cincinnati Society of Natural 1 History. 



growing specimens are somewhat moist, but they shrink little in drying 

 and become quite firm. The pores measure about .20 mm. in diameter. 

 It is an elegant species. 



B. Pores white. 



f. minute, round, obtuse. 



76. P. vitreus, Pers. Effused, subundulate, indeterminate, whitish, 

 subhyaline; the mycelium a tough, separable, subcoriaceous membrane. 

 Pores minute, round, long, obtuse, entire. 



Upon rotten prostrate trunks of Beech ; rare. A very remarkable- 

 species, which has given rise to other genera; Porta vitrea, Pers.; the 

 sterile leathery mycelium without any pores, Xylostroma eandidum, Pers. 

 The stratum of long pores is soft as if fleshy ; it is often interrupted or the 

 pores collected in nodules. The Xylostroma is usually found between the 

 bark and the wood. 



77. P. obducens, Pers. Effused, incrusting, innate, firm, white, 

 formed wholly of the pores. Pores minute, crowded, equal, distinctly 

 stratified, the older strata pale alutaceous. 



On the underside of old trunks ; common. The first year it consists 

 of a thin white separable stratum of crowded pores, which, however, in 

 drying takes on the pale alutaceous color of the succeeding years. It is 

 rather humid when young and differs decidedly from J\ vulgaris, which is 

 always dry and inseparable. 



78. P. vulgaris, Fr. Widely effused, thin, dry, closely adnate, 

 even, white ; the border soon glabrous. Pores firm, crowded, small, 

 iound, nearly equal. 



On wood of all sorts; common. Consisting of a thin dry stratum of 

 minute pores, sometimes on hard dry wood. The variety Jlavus, Fr., is 

 not uncommon and the white and yellow sometimes occur in the same 

 specimen; this is probably P. pulchellus, Schw. The pores are roundish 

 with rather thick dissepiments; they measure about .16 mm. in diameter. 



g. small, angular, acute. 



79. P. mucidus, Pers. Effused, rather thick, somewhat immersed, 

 soft, white, becoming pallid; the border indeterminate, byssine. Pores 

 medium, unequal, lacerate, received in a crustaceous mycelium. 



Upon old rotten wood; rare. At first soft and somewhat fleshy. 

 Pores becoming thin, angulate and torn, measuring about .20 mm. in 

 diameter. 



80. P. mollusens, Fr. Effused, thin, soft, white; the border 



