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

BOLETUS

373

8-15, wide and with ochraceous walls revived in KOH. Clamp connections absent. No amyloid hyphae present, but a fleeting-amyloid reaction does occur on the hymenophoral tissue and the spores.
Habit, habitat, and distribution.-Scattered to gregarious under
conifers, late summer and fall, sometimes locally abundant, as around
Marquette. Found especially in the pine country after heavy rains in late
August and September.
Observations.-This species ranks as one of the best edible fungi in
the state. However, no matter what species concept one subscribes to, B.
edulis is a "collective" species. Singer (1967) recognizes as subspecies
many of those we regard as species. The problem of how to classify all
the variants will involve much more careful field work than that done in
the past and more detailed studies on hyphal characters.
202a. Boletus edulis var. ochraceus Smith & Thiers, var. nov.
Pileus circa 12 cm latus, viscidus, luteus; cellulae terminales trichoderma saepe diverticulatae. Specimen typicum in Herb. Univ. Mich. conservatum est; prope Forestville, Marquette County, July 30, 1968, legit
J. Ammirati 2013. -
Pileus up to 12 cm broad, broadly convex, margin sterile for about
1 mm, glabrous, viscid and when dry sand particles become firmly imbedded in the cuticle, yellowish overall ("pale ochraceous-buff" on
margin to near "warm buff' on the disc), pale yellowish as dried. Context white, thick, with reddish tints just beneath cuticle, odor and taste
fungoid.
Tubes shallowly depressed, up to 1.5 cm deep, olive-ocher, unchanging when cut, drying dull yellow; pores dingy yellow, staining cinnamon to dull orange-cinnamon.
Stipe up to 14 cm long and 2.5 cm thick at apex, up to 3 cm or
more at base, clavate to subequal, solid, whitish to sordid brownish
("pinkish buff' tones in upper portion), finely reticulate above and
coarser below, when dried pale buff with reticulum pallid.
Spores 14-18 X 4.5-6 u, smooth, apex lacking a pore or a thin
spot, shape in face view fusiform, in profile elongate-inequilateral; color
in KOH olive-ochraceous, in Melzer's giving a fleeting-amyloid reaction
then weakly dextrinoid, wall thin (-0.3 gI).
Basidia 4-spored. Hymenophoral trama greenish blue as mounted
in Melzer's and viewed with a hand lens against white paper. Pleurocystidia scattered, 36-48 X 8-13 M, fusoid to fusoid-ventricose, apex subacute, content hyaline in KOH. Pileus cutis of a tangle of gelatinous