Genus BoletusGENUS BOLETUS
The species in the genus Boletus are numerous, and many are extremely beautiful. They are distinguished from the other pore-bearing fungi by the fact that their tubes are easily separable from each other and from the portion on which they are borne.
They are to be looked for in the warmest part of the season, and with a few exceptions will be found on the ground. As it is difficult to dry specimens so that they will retain their size, shape, and colour, careful notes should be taken of these points, together with the colour of the spores, the colour of the tubes, the colour of the flesh before and after being bruised, the character of the stem, the presence or absence of hairs and fibres on the several parts of the plant.
The genus Boletus contains many edible species, and also many which are dangerous : and as the recognition of the different species is a difficult matter, even for experts, the beginner should be especially cautious. In general it will be well to avoid for edible purposes all Boleti which change colour on exposure to the air or on being pressed: all those which have red-mouthed tubes, or mouths of a deeper colour than the rest of the tube; and all those with a peppery or acrid taste.
Experiment cautiously with the other species. A detailed description of the species can be found in "Boleti of the United States," or "Fuhrer fur Pilzfreunde."