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

BOLETUS Fries
Syst. Mycol. 1:385. 1821
Hymenophore tubular, the pores wide and angular to minute and
round; context distinctly fleshy and soon riddled by insect larvae or
decaying; basidiocarp consisting of a pileus, hymenophore, and stipe but
stipe not always central; spores more or less elongate-inequilateral in
most species and smooth to ornamented (but species with longitudinally
striate spores are segregated in Boletellus); spore deposit dull yellowbrown to amber-brown, cinnamon-brown, bister, olive-brown, olive, or
earth-brown (in air-dried deposits); stipe lacking ornamentation of squamules which become gray to dark brown or black at maturity or in age
(or in rare instances are colored from the beginning against a paler ground
color but which do not darken in aging).
Type species: Boletus edulis.
KEY TO SECTIONS
1. Spores ornamented but not by longitudinal lines or ridges; stipe more
or less lacerate-reticulate........................ Sect. Allospori
1. Spores not ornamented (though apex may be truncate)............. 2
2. Spores flattened (truncate) or notched at apex.......... Sect. Truncati
2. Spore apex unmodified.............................. 3
3. Hymenophore in age tending to become pinkish red throughout or in
part; taste acrid in some species; pileus subviscid or merely soft to the
touch.................................... Sect. Piperati
3. Not as above....................................... 4
4. Pores some shade of orange, red, dark brown to bay-brown when
young...................... Subsect. Luridi of Sect. Boletus
4. Pores not colored as above when young.................... 5
5. Stipe typically reticulate at least near apex; pores usually stuffed when
young.................................... Sect. Boletus
5. Stipe furfuraceous to pruinose or glabrous, at times coarsely ridged or
with a coarse wide-meshed reticulum but this not constant............. 6
6. Pileus unpolished to velvety or subtomentose.... Sect. Subtomentosi
6. Pileus glabrous and moist or viscid....................... 7
7. Stipe furfuraceous to punctate but ornamentation not darkening as in
Leccinum............................. Sect. Pseudoleccinum
7. Stipe more or less pruinose to naked............... Sect. Pseudoboleti

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