The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

Figs. 76-82: fig. 76, trichodermial hyphae from Boletus fraternus; figs.
77-78, normal and 1 abnormal spore of same; fig. 79, spores of B. rubeus; fig. 80,
cell from tramal hypha; fig. 81, trichodermial elements from pileus of B. rubellus;
fig. 82, spores from B. rubellus var. flammeus.