Phylum:Basidiomycota >> Class: Basidiomycetes >>  Order: Boletales 
 BCRC Number NO BCRC Number!  
 Scientific Name: Fuscoboletinus grisellus

Basionym: Boletinus grisellus Peck, Mem. N. Y. State Mus. 3: 169. 1900.

Fuscoboletinus grisellus (Peck) Pomerleau & Smith, Brittonia 14: 168. 1962.

 Description: Pileus 3-6 cm broad, obtuse to broadly conic; surface glabrous to appressed-fibrillose, slightly viscid beneath fibrils when fresh; color pale dull olive, becoming pallid to grayish olivaceous or occasionally tinted with yellow, avellaneous in age, at times drying dull brown; margin inrolled when young, often decorated with remnants of submembranous grayish veil; context thick, cottony, whitish or faintly olivaceous, unchanging when cut; odor and taste not distinctive. Tubes 3-5 mm long, adnate to decurrent, scarcely separable, pallid to grayish when young, in aged yellowish, finally dull brownish; pores concolorous with tubes, round to angular, often sublamellate in radiating lines. Stipe 5-9 cm long, 0.4-0.7 cm thick, equal, straight; surface somewhat reticulate above annulus, nearly glabrous below, whitish or pallid becoming yellowish, rarely bluish when handled; context solid, whitish above annular zone, becoming yellow below; veil submemranous, well-formed annulus rare. Spore deposit gray-brown to chocolate-gray. Spores 10.5-12.5 × 4-5 μm, smooth, broadly elliptic to subovate in face view, inequilateral with shallow suprahilar depression in profile, hyaline to pale olive gray in KOH, ochre in Melzer's. Basidia 30-35 × 7-8.5 μm, mostly clavate to subcylindric, thin-walled, 4-spored, sterigmata 4.5-5.5 μm long, basidioles often subglobose in clusters on short branch hyphae, hyaline in KOH, in Melzer's mostly pale yellow. Pleurocystidia 65-85 × 7-9 μm, mostly subcylindric with rounded apices, thin-walled, sometimes with coagulated and amorphous, then brown in KOH, fasciculate, incrusted at base of fascicle with brown granular material, mostly hyaline in KOH, ochre yellow in Melzer's. Cheilocystidia 60-80×5-8 μm, similar to pleurocystidia. Caulocystidia 26-35 × 7-10 μm, subcylindric to clavate, apices rounded, septate, terminal cell often expanded, thin-walled, mostly hyaline in KOH, numerous, mixed with scattered caulobasidia; cuticular hyphae at base of stipe of variously inflated cells, not considered to be caulocystidia. Tube trama interwoven type, hyaline in KOH, nonamyloid. Pileal cuticle consisting of parallel, nongelationous, radial hyphae that are 7-10 μm thick, light yellowish-brown to cinnamon color in KOH. No clamp connections were observed.

Taiwan, Taitung: Shiang-Yang, alt. 2,300 m, 14 Jul 2001, Chen CM. 2929.

 Habitat: Cespitose on humus in rocky soil of Pinus taiwanensis Hayata in summer.

Taiwan, North America, China (Sichuan, Yunnan, Tibet, Heilongjiang).


Chen, CM et al. 2003.


C. M. Chen

 Note: F. grisellus is distinguishable from other congeneric species by having a typical conic-umbonate pileus and submemranous veil, and having a well-formed annulus. Also, it is much less viscid than F. glandulosus. It has no characteristic squamules on pileus like those of F. ochraceoroseus and F. paluster.