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. [Illustration: 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.]