HYMENOMYCETES 365 



whereas towards the other pole or most modern end, 

 poisonous properties are very abundant. 



The species are annual, those in temperate zones are 

 mostly short-lived and putrescent, whereas the majority of 

 forms occurring in the tropics are dry, corky, and tough, 

 leading up to such genera as Lenzites, Panus, etc., which 

 form a transition to the Polyporaceae. 



Many species are edible, and a yet greater number are 

 poisonous. Edible and poisonous species often occur as 

 closely allied forms belonging to the same genus. 



Polyporeae 



The leading idea of the present family consists in the 

 hymenium being composed of a series of closely packed 

 tubes standing side by side, their free, open ends collec- 

 tively forming the surface of the hymenium. The entire 

 inner surface of each tube is covered with basidia and 

 other elements of the hymenium, the spores falling out of 

 the tubes into the air at maturity. In Polyporus, the central 

 and most typical genus included in the family, the tubes, as 

 seen in a section, are sometimes one to two centimetres 

 in length, the diameter varying from a quarter to one 

 millimetre. 



As would be expected, all genera are not equally typical, 

 those shadowing in the family from its predecessor, the 

 Basidiomycetes, naturally retaining some of the structural 

 features of that family. Among such may be noted the 

 genera Daedalea and Trametes, where the hymenium is 

 borne on irregular plates or gills radiating from the stem 

 to the circumference of the pileus ; but these gills are 

 variously connected by transverse walls, which are some- 



