The distinctive characteristics of these genera may be stated as follows:
| Pores compacted together and forming a continuous stratum | 1 | |
| Pores each a distinct tube, standing closely side by side | Fistulina | |
| 1. | Stem central, and stratum of spores easily separable from the cap | Boletus |
| 1. | Stratum of tubes not separating easily, cap covered with coarse scales | Strobilomyces |
| Stratum of tubes separating, but not easily; tubes arranged in distinct, radiating lines. In Boletinus porosus the tubes do not separate from the cap | Boletinus | |
| Stratum of pores not separable from cap; plant soft when young, but becoming hard, corky, stipitate, shelving | Polyporus | |
Boletus. Dill.
Boletus, a clod. There are very many species under this genus and the beginner will experience much trouble in separating the species with any degree of assurance. The Boletus is distinguished from the other pore-bearing fungi by the fact that the stratum of tubes is easily separable from the cap. In the Polyporus the stratum of tubes cannot be separated.
Nearly all Boleti are terrestrial and have central stems. They grow in warm and rainy weather. Many are very large and ponderous; fleshy and putrescent, decaying soon after maturity. It is important to note whether the flesh changes color when bruised and whether the taste is pleasant or otherwise. When I first began to study the Boleti there were but few species that were thought to be edible, but the ban has been removed from very many, even from the most wicked, Boletus Satanus.
Boletus scaber. Fr.
The Rough-Stemmed Boletus. Edible.
Figure 282.—Boletus scaber. Two-thirds natural size.