Boletus 



POLYPORACE^E 



317 



KEY TO THE GENERA. 



Terrestrial. 



Tubes easily separable from the hymenophore. Stem 



central 



Tubes not separable, very large with transverse dis- 

 sepiments. Stem central 



Mostly growing on trunks, stumps or wood. 



Stipitate to sessile. Tubes small, without dissepi- 

 ments. Substance fleshy, hard, tough or some- 

 what soft 



Sessile. 



Substance fleshy, juicy 



Substance woody 



Substance coriaceous, spongy or membranous. 



Pores round ... 



Pores oval or elongate 



Pores sinuous , 



Sessile to resupinate. Substance cartilagino-soft 



to subgelatinous 



Resupinate. 



Substance thin, woody or waxy 



Hymenophore covered with granules 



59 BOLETUS. 



60 STROBILOMYCES. 



62 POLYPORUS. 



61 FlSTULINA. 



63 FOMES. 



64 POLYSTICTUS. 



66 TRAMETES. 



67 D^DALEA. 



68 MERULIUS. 



65 PORIA. 



69 POROTHELIUM. 



LIX. BOLETUS Dill. 

 (From the clod-like shape of the pileus; Gr. bolos, 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. edulis 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 



