THE GENUS POLYPORUS. 



In the olden days all fungi with small pores were called Boletus. Persoon 

 divided them into two sections. First. The fleshy species with pores easily sep- 

 arable from the pileus, which constitute the genus Boletus as known at the present 

 time. Second. Those with the pores continuous with the context of the pileus. 

 The latter section was called Polyporus by Fries, which was accepted by Persoon 

 and generally used from the appearance of Fries' Systema up to the publication of 

 the sixth volume of Saccardo's Sylloge (1888). 



Fries in his Novae Symbolae (1851) proposed four main divisions of these 

 plants, viz: 



Fomes Perennial, pores in strata. 



Polyporus Fleshy annuals. 



Polystictus Coriaceous annuals. 



Poria Resupinate. 



Cooke attempted (a very poor attempt) to arrange the species under these four 

 heads, as genera, and Saccardo adopted Cooke's arrangement. Since the appear- 

 ance of Saccardo, these four genera have been generally adopted by writers on the 

 subject, and for practical purposes, are about as good for a general division as can 

 be devised. 



Beginning with Karsten, 1881, and ending, it is to be hoped, with Murrill in 

 the past few years, several have amused themselves (and others) by proposing in- 

 numerable "new genera," based chiefly on the old sections and subsections of the 

 Friesian system, getting up all kinds of excuses to give them new names and add 

 their own names to each species as the "authority." As it is very rarely that any 

 of these proposed changes have been based on a new principle of classification, and 

 as they have only added to the confusion with a jargon of new names, mycologists 

 as a usual thing, have honored such work by ignoring it. Personally, I do not con- 

 sider it of enough importance to cite in detail even as synonyms. 



The genus Polyporus, in the sense as intended in Saccardo and found in this 

 pamphlet, consists of soft, fleshy species, annuals, excepting in the tropics. The 

 distinction between Polyporus and Polystictus, which Fries evidently had in mind, 

 is that when growing, Polyporus is soft and fleshy, and usually moist, and becomes 

 brittle when dried, while Polystictus has dry, coriaceous or leathery textures when 

 growing. It is not always easy to decide on these characters especially from dried 

 specimens, and in practice the thick (or rarely thin) species that dry brittle are 

 called Polyporus, while the thin, flexible species are called Polystictus. We have con- 

 sidered the species of Polyporus under two general heads. First: those with a stipe 

 which we published in a previous pamphlet, The Stipitate Polyporoids, and, 

 second: the sessile species, included in this pamphlet. 



The history of Polyporus species is the general history of mycology. In Europe, 

 Persoon and Fries defined the most of the species, and the greater part of them are 

 taken in the sense of these authors. Most of the species can be easily and definitely 

 traced back to these authors, but in the section of white species it is very difficult 

 to decide from the scanty and often conflicting evidence what particular species 

 they had in view. Two men, in recent years in Europe, Bresadola and Romell, have 

 given critical studies of the history and identity of the Friesian species. We have 

 endeavored to learn the views of these men, as well as to hunt up and study all the 

 evidence that exists, and to form our own conclusions. That they are not always 

 in accord is unfortunate, but unavoidable. These differences will always exist, as 

 long as each author feels that it devolves on him to take names in their original 

 meaning, for in a number of cases investigators will arrive at different conclusions. 



In the United States the early work was done by Schweinitz, who proposed 

 as "new species" everything he did not determine (or misdetermine) as being 

 European. He got the cream of the valid, endemic species, and would no doubt 



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