Murrill: Polyporaceae of North America <>.'>9 



trunk. I have found it in this position quite frequently on the 

 trunks of shade trees in Washington, D. C. 



Berkeley's description was taken from specimens in the Hooker 

 herbarium collected in North America by Drummond and labeled 

 P. Drummondii by Klotzsch. Comparison of the type specimens 

 at Kew and Philadelphia shows the two species P. unicolor and P. 

 obtusus to be synonymous. Either name is a very suitable 

 one. 



This is a large and conspicuous plant, but rather hard to col- 

 lect on account of its arboreal habit. It has been found on dead 

 or partly decaying living trunks of oak, maple and a few other 

 deciduous trees. The pileus is quite soft and elastic when young 

 and the tubes are very long and become somewhat daedaleoid by 

 confluence as they grow older. Although abundant and well 

 known in some localities, the species has not been often reported : 

 New Jersey, Ellis, Meschutt ; Maryland, Maxon ; District of 

 Columbia, Murrill; Virginia, Murrill ; North Carolina, Schweinitz ; 

 Missouri, Demetrio ; Iowa, Hohvay ; Wisconsin, Baker. 



Species inquirendae 



Sistotrema spongiosum Schw. Syn. Fung. Car. 75. 18 18. 

 Polyporus labyrinthicus Fr. Elench. Fung. 83. 1828. Described 

 from North Carolina plants collected on living or recently fallen 

 trunks. Discussed at some length by Fries, who received speci- 

 mens from Schweinitz. In their commentary, Berkeley and Curtis 

 say it is remarkable for its coarse, tow-like texture, but they do 

 not associate it with any better known name or species. 



There are many reasons for believing this species to be a near 

 ally of P. unicolor. All the descriptions point to an old specimen 

 of this latter plant in which the tubes have become quite daedaleoid 

 and the dissepiments broken up. A sheet of specimens at Kew 

 labeled P. labyrinthicus from Plowright's herbarium shows well the 

 characters of P. unicolor. They may not be authentic, however, 

 though they seem old enough to be so considered. On the same 

 sheet at the bottom are the specimens of P. Icucospongia sent from 

 Harkness with their original label, P. labyrinthicus, just as he sent 

 them. These are the cause of the confusion of the two species, as 

 we see it in Saccardo's Sylloge, for example. 



