This section is from the book "Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc.", by George Francis Atkinson. Also available from Amazon: Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc..
This species has been reported from New York State by Peck. During September, 1899, I found it quite common in the Blue Ridge mountains of North Carolina, at an elevation of between 4000 and 5000 feet. It grows on the ground in mixed woods. The plants are 5-8 cm. high, the caps 5-7 cm. broad, and the stem 6-10 mm. in thickness.
Boletus americanus. Cap slimy, yellow, sometimes with reddish spots, tubes yellowish (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 8-10x4-5 µ. Figure 172 is from plants (No. 4067 C. U. herbarium) collected at Blowing Rock, N. C. It is closely related to B. gramilatus and by some is considered the same.
Boletus punctipes. Cap viscid when moist, reddish brown, pink, yellow, tawny, etc., tubes yellowish, stem dark punctate (natural size). Copyright.