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Page number:1112 
Remarks (internal):An excellent color reproduction of Clitocybe atrialba may be found in Smith (1949, Reel 17, No. 114). It is the largest species in Clitocybula and apparently is confined to the Pacific coast. As Smith (1949) noted, there is some resemblance in the field between C. atrialba and Clitocybe avellaneialba Murrill which occurs in the same area. The spores of the latter of course are nonamyloid and fusoid, and it seems unlikely that there is any close relation between the species.
Description type:Non-original description 
Description:Clitocybula atrialba (Murrill) Singer, Sydowla 15; 53. (1961) 1962. Figs. 17-20
Clitocybe atrialba Murrill, Mycologia 5: 207. 1913.
Fayodia atrialba (Murr.) Singer, Lloydia 5: 127. 1942.
Pileus 2.5-8(-10) cm broad, convex at first expanding to plane, disc soon depressed, finally infundibuliform, margin at first decurved then elevated, arched at times, entire or crenate, not striate, surface somewhat canescent or finely matted fibrillose, becoming furfuraceous, moist at times but not hygrophanous, smoky to dark blackish brown ("blackish brown") , usually streaked with lighter brown and paler on the disc; context thin, whitish near disc ("tilleul buff"), concolorous with pileus near margin. Odor and taste not distinctive.
Lamellae decurrent, ends even and forming a collar on stipe apex, distant, narrow or broad, intervenose, faces venose and occasionally forked in age, grayish ("tilleul buff," "smoke gray").
Stipe 6-10.5(-12) cm long, apex 4-12 mm thick, base somewhat enlarged and often with rhizomorphs, surface diffracted scaly to furfuraceous at apex, fibrillose streaked downward, apex with ridges as continuation from lamellae, brown ("buffy brown," "olive brown"), paler in age.
Spores (6-) 7.5-9 x 7-8 µm, from 4-spored basidia, globose or subglobose, up to 13 x 9 µm from 1- and 2-spored basidia, then broadly elliptic to subovate, smooth, amyloid, deposit white. Basidia (30-)36-50(-56) x 6.5-9.5 µm, often 2-spored, occasionally 4-spored and 1-spored. Cystidia not found on lamellae. Pileus cutis brown in KOH, pigment intracellular, consisting of interwoven pilocystidia, protruding irregularly or recumbent, clavate to clavate-bulbous or fusoid or irregularly inflated, often pedicellate, 20-63 µm long, 4-15.5 µm in diam, walls thickened at times, subsurface hyphae cylindric or inflated, up to 14 µm in diam, contents brown, walls thin and smooth; context hyphae cylindric or inflated, 2-20 µm. in diam, hyaline. Hymenophoral trama of interwoven to undulate-subparallel hyphae, mostly cylindric, 2-15 µm in diam, hyaline. Oleiferous hyphae present occasionally, 2-8 µm in diam. Clamp connections present. Caulocystidia present, brown in KOH, clavate-pedicellate, 27-75 µm long, 5-10 µm in diam, walls thin.
Solitary, scattered or subcespitose. On buried wood (alder, oak) or less commonly on logs and sticks above ground. September and October (December in California).
Material examined. Representatives (of 32 collections): U. S. A. California: Smith 56089 (MICH). Oregon: Smith 79639 (MICH). Washington: Bigelow 2103 (MICH); Murrill 259 (type) (NY).
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