Boletus vermiculosus Pk.—This species was named B. vermiculosus because it is sometimes very "wormy." This is not always the case, however. It grows in woods on the ground, in the Eastern United States. It is from 6–12 cm. high, the cap from 7–12 cm. broad, and the stem 1–2 cm. in thickness.
The pileus is thick, convex, firm, smooth, and varies in color from brown to yellowish brown, or drab gray to buff, and is minutely tomentose. The flesh quickly changes to blue where wounded, and the bruised portion, sometimes, changing to yellowish. The tubes are yellowish, with reddish-brown mouths, the tube surface being rounded, free or nearly so, and the tubes changing to blue where wounded. The stem is paler than the pileus, often dotted with short, small, dark tufts below, and above near the tubes abruptly paler, and sometimes the two colors separated by a brownish line. The stem is not reticulated. Figure [169] is from a photograph of plants (No. 4132 C. U. herbarium) collected at Blowing Rock, N. C., during September, 1899.
Boletus obsonium (Paul.) Fr.—This species was not uncommon in the woods at Blowing Rock, N. C., during the latter part of August and during September, 1899. It grows on the ground, the plants usually appearing singly. It is from 10–15 cm. high, the cap 8–13 cm. broad, and the stem 1–2 cm. in thickness, considerably broader at the base than at the apex.
The pileus is convex to expanded, vinaceous cinnamon, to pinkish vinaceous or hazel in color. It is soft, slightly tomentose, and when old the surface frequently cracks into fine patches showing the pink flesh beneath. The thin margin extends slightly beyond the tubes, so that it is sterile. The flesh does not change color on exposure to the air. The tubes are plane, adnate, very slightly depressed around the stem or nearly free, yellowish white when young, becoming dark olive green in age from the color of the spores. The tube mouths are small and rotund. The spores caught on white paper are dark olive green. They are elliptical usually, with rounded ends, 12–15 × 4–5 µ. The stem is white when young, with a tinge of yellow ochre, and pale flesh color below. It is marked with somewhat parallel elevated lines, or rugæ below, where it is enlarged and nearly bulbous. In age it becomes flesh color the entire length and is more plainly striate rugose with a yellowish tinge at the base. The stem tapers gradually and strongly from the base to the apex, so that it often appears long conic.
The plant is often badly eaten by snails, so that it is sometimes difficult to obtain perfect specimens. Figure [170] is from a photograph of plants (No. 4092 C. U. herbarium) from Blowing Rock, N. C.
Boletus americanus Pk.—This species occurs in woods and open places, growing on the ground in wet weather. It occurs singly or clustered, sometimes two or three joined by their bases, but usually more scattered. It is usually found under or near pine trees. The plant is 3–6 cm. high, the cap 2–7 cm. broad, and the stem is 4–8 mm. in thickness. It is very slimy in wet weather, the cap is yellow, streaked or spotted with faint red, and the stem is covered with numerous brown or reddish brown dots.
The pileus is rounded, then convex, becoming nearly expanded and sometimes with an umbo. It is soft, very slimy or viscid when moist, yellow. When young the surface gluten is often mixed with loose threads, more abundant on the margin, and continuous with the veil, which can only be seen in the very young stage. As the pileus expands the margin is sometimes scaly from remnants of the veil and of loose hairs on the surface. The cap loses its bright color as it ages, and is then sometimes streaked or spotted with red. The tube surface is nearly plane, and the tubes join squarely against the stem. The tubes are rather large, angular, yellowish, becoming dull ochraceous. The stem is nearly equal, yellow, and covered with numerous brownish or reddish brown glandular dots. No ring is present.
This species grows in the same situations as the B. granulatus, sometimes both species are common over the same area. Figure [171] is from plants (No. 3991 C. U. herbarium) collected at Blowing Rock, N. C., September, 1899. The species is closely related to B. flavidus Fr., and according to some it is identical with it.
Boletus granulatus L. Edible.—This species is one of the very common and widely distributed ones. It grows in woods and open places on the ground. Like B. americanus, it is usually found under or near pines. It occurs during the summer and autumn, sometimes appearing very late in the season. The plants are 3–6 cm. high, the cap is 4–10 cm. broad, and the stem is 8–12 mm. in thickness. The plants usually are clustered, though not often very crowded.