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Family and Generic Descriptions

| Boletaceae | | Boletus | | Gastroboletus | | Gyroporus |
| Leccinum | | Pulveroboletus | | Suillus | | Tylopilus |


Flore Env. Paris, p. 248. 1926. (as "Ordre")

Homobasidiomycetous basidiocarp agaricoid, fleshy, putrescent, centrally stipitate; hymenophore tubulose; hymenium on inner surface of hymenophore; basidiospores smooth or variously roughened, globose to ellipsoid to cylindric or terete, brown, yellow to pink or vinaceous in mass; cystidia typically present, often incrusted and sometimes clustered; tube trama bilateral, at least in young basidiocarps; cuticle typically a trichodermium, rarely a cutis; clamp connections present or absent; typically mycorrhizal; terrestrial, rarely lignicolous.


Syst. Mycol. 1:385. 1821.

Pileus small to large or massive, most frequently convex or pulvinate, becoming plane to plano-convex or shallowly depressed; surface frequently dry to moist, rarely subviscid to viscid, glabrous to tomentose to appressed fibrillose or fibrillose scaly, white to yellow to various shades of red, pink, or brown to fuscous or blackish; margin typically entire, with no false veil; context white to pallid or yellow, sometimes with reddish or brownish stains, unchanging or often becoming blue when bruised or exposed, less often changing to other colors; taste mild to bitter or acrid, odor usually mild. Tubes 0.5-2 cm long, white to yellow, often changing color when bruised; pores 0.5-3 mm broad, angular, concolorous with tubes or pink to red to reddish brown, often bluing or changing to some other color when bruised. Stipe equal to clavate to ventricose or bulbous; surface smooth to longitudinally striate to reticulate, dry to moist, rarely viscid, no annulus or veil; color variable, often white to pallid to various shades of yellow, red, or brown. Spores brown to olive brown in mass, smooth, cylindric to subfusoid to subellipsoid; cystidia solitary, often embedded, sometimes staining in KOH or Melzer's reagent, variable in shape and size. Tube trama divergent. Cuticle typically a trichodermium, less commonly a cutis or ixotrichodermium. Clamp connections absent.


Beih. Bot. Centralbl. 422:273. 1926.

"Pileus" up to 8 cm broad, generally convex but typically highly irregular in outline and shape, especially with age, sometimes only partially coming above ground; surface dry to moist to subviscid, glabrous to tomentose to appressed fibrillose, sometimes appressed fibrillose-scaly; white to pallid to yellow brown to reddish brown to red; margin incurved, often highly irregular (peridium extending from margin over most of the gleba in G. subalpinus); context 1-2 cm thick, white to yellow, unchanging or becoming pinkish or blue when exposed; taste and odor typically mild. "Tubes" 1-2 cm long, highly irregular in arrangement, often not vertically oriented, white to yellow, unchanging or changing to blue when bruised; pores up to 1 mm broad, angular, concolorous to sometimes red or reddish. Stipe-columella typically present, often poorly developed and sometimes eccentric in attachment. Spore print not obtainable; spores ellipsoid to oblong to subovoid, ochraceous in KOH, smooth, walls thin to moderately thick. Hymenial cystidia scattered to abundant, sometimes clustered, clavate to fusoid to fusoid-ventricose, staining dark brown to black in KOH in at least one species. Tuba trama divergent to parallel. Cuticle a trichodermium, sometimes approximating a cutis. Clamp connections absent.


Enchir. Fung. p. 161. 1886.

Pileus up to 12 cm broad, convex to broadly convex becoming plane to shallowly depressed to plano-convex with age; surface dry to moist, glabrous to tomentose to appressed fibrillose to occasionally squamulose or woolly, pallid to buff to tan to brown; margin entire, incurved; context white, unchanging or changing to blue, sometimes rapidly and intensely so (context unchanging in G. castaneus); taste and odor mild. Tubes up to 8 mm long, white to very pale yellow when young, becoming bright yellow with age, unchanging or becoming blue in some when bruised; pores round to obscurely angular, one to two per millimeter, concolorous. Stipe up to 10 cm long, centrally attached, equal to clavate, typically hollow, at least in basal portion with age; surface glabrous to tomentose to appressed fibrillose (no annulus or veil in G. castaneus), pallid to buff to cinnamon to brown, unchanging or changing to blue when bruised. Spores yellow in deposit, hyaline in KOH, short ellipsoid, smooth, thin-walled. Hymenial cystidia abundant, hyaline, thin-walled, fusoid to fusoid-ventricose. Tube trama divergent. Cuticle a trichodermium or cutis. Hyphae of stipe transversely or horizontally arranged.Clamp and false clamp connections present.


Nat. Arr. Brit. Pls. 1:640. Emended Snell, 1942.

Pileus typically large, convex to pulvinate, becoming pIano-convex to plane; surface dry to moist, less frequently subviscid or viscid, tomentose to velutinous to sometimes appressed fibrillose or rarely appressed fibrillose-scaly, white to whitish to gray or pink to orange to orange red to maroon; margin entire or with sterile "flaps" of cuticle tissue; context white, unchanging or becoming fuscous or blackish when exposed, in some passing through a reddish phase before darkening; taste and odor mild. Tubes 0.5-2 cm long, typically white to smoky gray or rarely pale yellow when young, becoming olive to dingy yellow with age; pores typically small, concolorous, often staining vinaceous or brown when bruised. Stipe stout, often clavate, solid; surface dry, conspicuously ornamented with small dots or squamules, ornamentations often white to tan when young, typically becoming brown or black with age, no annulus; context white, unchanging or changing as in pileus, sometimes changing to blue in base of stipe. Spores brown to dark brown in mass, ochraceous in KOH, often up to 17-20 um long, subellipsoid to subfusoid, smooth. Hymenial cystidia scattered, often inconspicuous, hyaline, thin-walled, clavate to mucronate to fusoid-ventricose, usually not staining in KOH. Tube trama divergent. Pileus cuticle a tangled trichodermium, cells often disarticulating, pigment globules forming in some when mounted in Melzer's reagent. Stipe cuticle with numerous clusters of caulocystidia. Clamp connections absent.


Mycologia 1:9. 1909.

Pileus convex to plano-convex becoming plane to piano-convex; surface, at least when young, covered with an intensely yellow veil that obscures the surface color, dry, pulverulent, moist to subviscid or viscid when veil removed, pinkish cinnamon to brown, often with reddish streaks or spots, frequently pink to reddish with age; margin incurved, often with conspicuous veil fragments attached; context white to pale yellow, slowly changing to blue when exposed; taste mild to acid, odor mild. Tubes 0.5-1.5 cm long, yellow during all stages, changing to blue when bruised; pores up to 1 mm broad, angular, concolorous. Stipe up to 11 cm long, equal to tapering slightly toward the apex; surface dry to subviscid, covered with bright yellow veil, at least when young. Spores olive brown in mass, fusoid to ovoid, smooth, thin-walled, pale ochraceous in KOH. Hymenial cystidia scattered to numerous, hyaline to yellow in KOH, clavate to fusoid to subcylindric. Tube trama divergent. Cuticle loosely interwoven, no sphaerocysts in veil. Clamp connections absent.


Emended by Smith and Thiers
Contr. Toward a Monogr. of N. A. Sp. of Suillus, 1964.
Suillus S. F Gray, Nat. Arr. Brit. Pls.. 1:646. 1821.

Pileus convex to plane to occasionally umbonate or depressed; surface dry to moist to subviscid or viscid or glutinous, in California most frequently viscid, glabrous or streaked to appressed fibrillose to fibrillose-scaly, pale tan or buff to pallid vinaceous to yellow, unchanging with age or becoming yellow to brown; margin sometimes with conspicuous cottony roll (false veil), especially when young; context white or yellow, unchanging or becoming blue or very rarely reddening when exposed; taste and odor mild or rarely acid. Tubes 0.5-2 cm long, pallid to yellow during all stages of development; pores 0.5-3(5) mm broad, angular, concolorous, sometimes radiately arranged. Stipe central, equal to rarely clavate or ventricose, pallid to yellow; surface dry to subviscid or viscid, often noticeably glandulose; annulus present or absent. Spores olive brown in mass, subellipsoid to subcylindric to subfusoid, pale ochraceous in KOH, walls smooth, relatively thin. Cystidia solitary or clustered or fascicled, hyaline, becoming dark brown to almost black to occasionally vinaceous in KOH, clavate to cylindric. Hymenophoral trama divergent. Cuticle a trichodermium or ixotrichodermium. Clamp connections absent in California species. Forms mycorrhizal associations with conifers, especially pines and Douglas fir.


Rev. Mycol. 3:16. 1881.

Pileus moderate to large, convex to piano-convex to plane; surface dry to moist, not truly viscid, glabrous to more commonly tomentose or fibrillose, pallid to tan or pale vinaceous to very dark brown or blackish, often becoming brown or blackish; margin entire; context pallid, often changing to blue when exposed, sometimes eventually becoming brown. Taste and odor usually mild. Tubes 1-2 cm long, white to buff to pale pink or vinaceous (dark reddish brown in T. pseudoscaber); pores angular, concolorous, often changing to another color when bruised. Stipe usually equal; surface more or less smooth or reticulate, glabrous to pruinose or rarely appressed fibrillose, no annulus or veil, white to pallid becoming brown to brownish vinaceous (dark sooty brown during all stages in T. pseudoscaber). Spores flesh color to vinaceous to dark reddish brown in deposit, hyaline to ochraceous tawny in KOH, subellipsoid to subfusoid to subcylindric, smooth. Hymenial cystidia solitary, hyaline, sometimes appearing incrusted, clavate to fusoid to fusoid-ventricose. Tube trama divergent. Cuticle a trichodermium or rarely a cutis. Clamp connections absent.

The Boletes of California
Copyright © 1975 by Dr. Harry D. Thiers
Additional content for the online edition © 1998 by Michael Wood, Fred Stevens, & Michael Boom
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