Figure 172.—Boletus punctipes. Cap viscid when moist, reddish brown, pink, yellow, tawny, etc., tubes yellowish, stem dark punctate (natural size). Copyright.
The pileus is convex, sometimes becoming nearly plane, and it is quite thick in the center, more so than the granulated boletus, while the margin is thin, and when young with a minute gray powder. The margin often becomes upturned when old; the cap is viscid when moist, dull yellow. The tubes are short, their lower surface plane, and they are set squarely against the stem. They are small, the mouths rounded, brownish, then dull ochraceous, and dotted with glandules. The stem is rather long, proportionately more so than in the granulated boletus. It distinctly tapers upwards, is "rhubarb yellow," and dotted with glandules. This character of the stem suggested the name of the species. The spores are 8–10 × 4–5 µ. Figure [172] is from plants (No. 4067 C. U. herbarium) collected at Blowing Rock, N. C. It is closely related to B. granulatus and by some is considered the same.
Boletus luteus Linn. (B. subluteus Pk.) This species is widely distributed in Europe and America, and grows in sandy soil, in pine or mixed woods or groves. The plants are 5–8 cm. high, the cap 3–12 cm. in diameter, and the stem 6–10 mm. in thickness. The general color is dull brown or yellowish brown, and the plants are slimy in moist weather, the stem and tubes more or less dotted with dark points. These characters vary greatly under different conditions, and the fact has led to some confusion in the discrimination of species.
Figure 173.—Boletus luteus. Cap viscid when moist, dull yellowish to reddish brown, tubes yellowish, stem punctate both above and below the annulus (natural size). Copyright.
The pileus is convex, becoming nearly plane, viscid or glutinous when moist, dull yellowish to reddish brown, sometimes with the color irregularly distributed in streaks. The flesh is whitish or dull yellowish. The tube surface is plane or convex, the tubes set squarely against the stem (adnate), while the tubes are small, with small, nearly rounded, or slightly angular mouths. The color of the tubes is yellowish or ochre colored, becoming darker in age, and sometimes nearly brown or quite dark. The stem is pale yellowish, reddish or brownish, and more or less covered with glandular dots, which when dry give a black dotted appearance to the stem. In the case of descriptions of B. luteus the stem is said to be dotted only above the annulus, while the description of B. subluteus gives the stem as dotted both above and below the annulus. The spores are yellowish brown or some shade of this color in mass, lighter yellowish brown under the microscope, fusiform or nearly so, and 7–10 × 2–4 µ. The annulus is very variable, sometimes collapsing as a narrow ring around the stem as in Fig. [173], from plants collected at Blowing Rock, N. C., September, 1899 (B. subluteus Pk.), and sometimes appearing as a broad, free collar, as in Fig. [174]. The veil is more or less gelatinous, and in an early stage of the plant may cover the stem as a sheath. The lower part of the stem is sometimes covered at maturity with the sheathing portion of the veil, the upper part only appearing as a ring. In this way, the lower part of the stem being covered, the glandular dots are not evident, while the stem is seen to be dotted above the annulus. But in many cases the veil slips off from the lower portion of the stem at an early stage, and then in its slimy condition collapses around the upper part of the stem, leaving the stem uncovered and showing the dots both above and below the ring (B. subluteus).
