POLYPORALES 



447 



ancestral form of basidia. In good nourishment the conidiophores branch 

 and form coremia. 



Some species are used as food, e.g., Polyporus confluens, P. frondosus, 

 P. pes-caprae and P. sulphureus; earlier, others were used as medicines 

 (Fomes officinalis from its quinine taste) ; others found technical uses, as 

 P. betulinus in the manufacture of charcoal crayons. Still others cause 

 disease of fruit and forest trees and destroy timber, as Fomes igniarius, 

 F. fomentarius, from whose fructifications tinder was formerly made, 

 Polyporus squamosus and P. sulphureus and, 

 on old gooseberries and currants, Fomes Ribis. 



The fructifications of Fomes igniarius grow 

 to as much as eighty years old forming a new 

 layer each year. A few species of Polyporus 

 form sclerotia up to the size of a human head, 

 as P. Tuberaster (E. Fischer, 1891) in the north 

 temperate zone, P. Berkeleyi, P. umbellatus 

 and P. frondosus in the United States, P. sacer 

 and P. Goetzii in Africa, P. Sapurema in Brazil, 

 P. rhinocerotis in the Malay region and P. 

 basilapidiodes and P. Mylittae in Australia. 

 Those of P. Mylittae attain a weight of 15 kg. 

 and earlier were eaten by the natives in 

 Australia and called native bread. 



The species of Polystictus, which number 

 almost a thousand, are saprophytes on wood. 

 P. versicolor often attacks fruit trees as a 

 wound parasite. P. pargamenus causes decay 

 of a large number of woods. 



Trametes, as its character is not always 

 recognizable, has been divided by many 

 authors among the above three genera and Daedalea (Fig. 288). 

 Trametes Pini causes great damage to pines by a red rot of wood. Under 

 certain conditions of nourishment, their hyphae (as in most other Poly- 

 poraceae) fall apart into oidia. 



Hyaline, pyriform or oval conidia have been noted in Cryptoporus 

 volvatus (Zeller, 1915). The hymenium develops on the roof of a large 

 central cavity opened in the interior of a spherical fructification, laterally 

 attached to the substrate. Gradually the portion below the hymenium 

 ceases to grow, the hyphae are stretched into a thinner layer and a small 

 central opening is formed in the veil (" volva"). The spores are shed upon 

 the upper side of the veil, whence they are dispersed by clinging to the 

 legs of insects which crawl over it. The development is therefore hemi- 

 angiocarpous, the only case known in the Polyporales and the only group 

 in this order which depends on insects for spore dissemination. 



Fig. 288. — Trametes species 

 on wood. Lower view of 

 bracket fructifications showing 

 Daedalea-like elevations of hy- 

 menophore. (Natural size; 

 after Falck, 1909.) 



