Summary:
Features include 1) small, cup-shaped, grayish brown to blackish fruitbodies, 2) distant, strikingly white gills, 3) growth on dead twigs of woody dicotyledonous plants, 4) curved spores, and 5) inconspicuous metuloids.

Cap:
0.2-0.6cm across, cupulate [cup-shaped], pendent, or conchate [shell-shaped], dorsally or laterally attached; grayish brown to almost black; "appearing glabrous and translucent-striate when fresh and moist", "drying black, opaque, with fine white floccose bits or wisps over surface", margin even or slightly wavy, (Thorn(5) who also describes cap as having "fine white wisps or scales")

Flesh:
thin, not gelatinous; whitish, (Buczacki)

Gills:
"radiating from a near central point on underside", distant, "narrow to moderately thick", "occasionally becoming slightly tortuous-anastomosing"; stark white, becoming faintly grayish; smooth or finely frosted under 10X, (Thorn(5)), radiating from a near central point on the underside, distant, narrow; striking white becoming only faintly grayish at maturity, (Watling), usually narrow, distant, (Thorn(2))

Odor:
faint, mealy, (Buczacki)

Taste:
faint, mealy, (Buczacki)

Microscopic spores:
spores (7.5)8-10(11.5) x 2.8-3.8(4.2) microns, broadly allantoid [curved-sausage-shaped], smooth, inamyloid, colorless; basidia 4-spored, (21)26-30 x 6.2-8 microns, clavate, with pale brown bases, basidioles also present with brown bases; cheilocystidia 18-38 x 4-7 microns, "fusoid-capitate, with well-formed or poorly formed hour-glass, occasionally branched", hour-glass 4-6.5 x 1.2-2.0(2.5) microns, mucoid ball at tip 5-8 microns in diameter, [the cystidia illustrated as having a constriction below a head that has a mucoid ball surrounding it or having one or more tenpinlike (hourglass-like) appendages the head of which may have a mucoid ball surrounding it]; metuloids 21-40 x 4.5-7 microns, not projecting (resembling basidioles), clavate or fusoid, thin-walled (up to 0.5 microns thick), brilliant magenta in cresyl blue, apices entirely obscured by conic or ovoid crystalline masses 8-12(16) microns wide and 12-20 microns tall, bases pale brown but darker than bases of basidia and basidioles; hymenium 25-37 microns deep, "hyaline at gill edges, with hyaline apices and brown bases in interstices"; subhymenium 5-10 microns wide, "indistinct, blending in colour from trama to hymenium, medium brown (interstices) to subhyaline (gill edges)", hyphae 1.5-3 microns wide; gill trama quite interwoven, pale beige in KOH above, becoming colorless near gill margins; trama 30-50 microns deep, densely tangled, clay brown in KOH, becoming paler toward the gill trama, hyphae mostly parallel, radially arranged, (1)3-7 microns wide, "smooth or finely encrusted, thin-walled"; gelatinous zone 220-300 microns deep, hyphae in a loose tangle, 1-4(5) microns wide, "most smooth, but a few near cuticle finely spiral-encrusted"; cap cuticle 15-20 microns deep, "black or dark brown in KOH, a repent tangle of heavily spiral-encrusted brown hyphae" (1.5)2-5(6) microns wide, with a few fine, loose ends 1.5-2 microns wide, terminating in small hourglass-shaped cells 3-4.5 x 1.5-1.7 microns, surrounded by a mucoid ball 3-4(6) microns in diameter; all hyphae with single clamp connections, (Thorn(5)), spores 7.5-10 x 2.8-3.8(4.2) microns, allantoid, smooth, inamyloid, colorless; basidia 4-spored, 26-30 x 6-8 microns, clavate; pleurocystidia 12-20 x 8-12(16) microns, "metuloid, clavate to fusoid, thin-walled, pale brown at base and brilliant magenta in cresyl blue", with conic or ovoid crystalline apical material, cheilocystidia 20-45 x 5-10 microns, fusiform, capitate to hourglass-shaped, with apical mucoid ball; cap cuticle "of light yellowish brown, contorted, fusiform to capitate cystidia" similar to cheilocystidia intermixed with yellowish granular encrusted hyphae in a gelatinous matrix with hyphae 2-4 microns broad; clamp connections present, (Watling based on Thorn & Miller)

Spore deposit:
white (Thorn(5), Watling)

Notes:
Collections were examined from ON, Italy, (Thorn), and United Kingdom (Watling). Several collections from BC identified by Paul Kroeger and deposited at the University of British Columbia.

EDIBILITY

Synonyms and Alternate Names:
Pleurotus cyphelliformis (Berk.) Sacc.