Boletus 



POLYPORACE/E 



317 



Key to the Genera. 



Terrestrial. 



Tubes easily separable from the hymenophore. Stem 



central 59 Boletus. 



Tubes not separable, very large with transverse dis- 

 sepiments. Stem central 60 Strobilomyces. 



Mostly growing on trunks, stumps or wood. 



Stipitate to sessile. Tubes small, without dissepi- 

 ments. Substance fleshy, hard, tough or some- 

 what soft 62 Polyporus. 



Sessile. 



Substance fleshy, juicy 61 Fistulina. 



Substance woody 63 Fomes. 



Substance coriaceous, spongy or membranous. 



Pores round .. 64 POLYSTICTUS. 



Pores oval or elongate 66 Trametes. 



Pores sinuous 67 D^edalea. 



Sessile to resupinate. Substance cartilagino-soft 

 to subgelatinous 68 Merulius. 



Resupinate. 



Substance thin, woody or waxy 65 Poria. 



Hymenophore covered with granules 69 Porothelium. 



LIX. BOLETUS Dill. 

 (From the clod-like shape of the pileus; Gr. fro/os, a clod.) 



Veil universal, forming an annulus, perfect to imperfect or 

 obsolete. Pileus fleshy. Stem central, fleshy, continuous and homO- 



Fig. 73- — a, section of Boletus luteus L., showing gelatinous mem- 

 branous veil. B, section of B. ednlis Bull., showing at * tubes 

 separating from hymenophore. c, section of B. cyanescens Bull., 

 young example showing universal floccoso-scaly veil. One-third 



natural size. 



geneous with the hymenophore, annulate to simple. Tubes distinct 

 from the hymenophore, connected in a stratum, the surface of which 



