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

BOLETUS

343

Habit, habitat, and distribution.-Solitary in low rich hardwoods,
Ann Arbor, September 25, 1965, Florence Hoseney (Smith 72721).
Observations.-The Eber White Woods in Ann Arbor has been maintained as a nature study area. In Michigan the only other member of
this stirps, which lacks a color change to blue on the injured context or
tubes, is B. holoroseus. The latter has little in common with B. eberwhitei. The latter is close to B. appendiculatus and B. impolitus, but
the combination of characters does not agree with either one.
185. Boletus frostii Russell in Frost
Bull. Buff. Soc. Nat. Sci. 2:102. 1874
Suillellus frostii (Russell) Murrill, Mycologia 1:17. 1909.
Boletus alveolatus Berkeley & Curtis in Frost, Bull. Buff. Soc. Nat. Sci. 2:102.
1874.
Suillus frostii (Russell) Kuntze, Rev. Gen. Pi. 3(2):535. 1898.
Illus. Pls. 136-37.
Pileus 5-13 (15) cm, hemispheric to convex becoming broadly convex to plane to shallowly depressed, or the margin turned up in age;
margin incurved, sterile; surface hoary at first but soon shining, sometimes appearing finely areolate, viscid from a gelatinous pellicle, dark
blood-red to blackish red at first ("garnet-red" to "Morocco-red" or
"Brazil-red"), fading with age, typically blood-red with yellowish areas
when old. Context up to 2.5 cm thick, pallid to pale yellow (lemonyellow), turning blue immediately upon exposure; odor none, taste mild
(cuticle acid to the tongue at times).
Tubes (5) 9-15 mm deep, adnate becoming depressed, with decurrent lines down the apex of the stipe, yellow to olivaceous yellow
("mustard-yellow"), dingy blue when bruised; pores small, 2-3 per mm,
round (stuffed at first-Coker), deep red ("madder-brown" to "Moroccored") until old age but finally a paler red, pore surface typically beaded
with yellowish droplets when young and readily staining dingy blue
when bruised.
Stipe 4-12 cm long, 1-2.5 cm thick at apex, equal to tapering
toward apex to occasionally ventricose, solid, white within above,
yellowish downward, surface dry, very coarsely reticulate to laceratereticulate overall and dark blood-red, often yellow at base or whitish,
showing a slight change to blue when bruised (often none in the yellow
base).
Spore deposit "olive-brown"; spores 11-15 X 4-5 p, occasional
giant spores up to 18 pi long also present; shape in face view narrowly