Summary:
Features include small size, hygrophanous, cream buff to yellow, striate cap with paler to white margin, whitish gills without colored edges, white to pale yellow stem that is pruinose at the top, and microscopic characters including inamyloid spores, smooth, fusiform cheilocystidia, and only weakly dextrinoid gill trama. Smith(1) considered it rare but said that it occurs in large quantities in certain locations. Smith(1) described var. microspora (of Mycena flavoalba) from WA and occurring in ID, with spores 5-6 x 3 microns, but Maas Geesteranus remeasured spores as larger and does not accept this variety. The description of A. flavoalba used here is derived from Smith(1).

Cap:
1-2(2.5)cm across, obtusely to sharply conic with appressed margin becoming obtusely bell-shaped, sometimes cap center with abrupt papilla, sometimes flattened, margin flaring when mature or slightly recurved [upcurved]; hygrophanous, "cream buff" to clearer yellow at first, the margin paler and almost white, fading to "cartridge buff" on the disc and a dead yellowish white along the margin (buttons pink in one variant turning to yellow or keeping a slight pinkish tinge around disc); smooth, bald, translucent-striate^, (Smith), pale yellowish to ochraceous at center, paler to white toward the margin, (Maas Geesteranus)

Flesh:
thin except under disc, fragile; yellowish to white

Gills:
ascending and somewhat uncinate or with tooth, close to somewhat distant (18-24 reaching stem), narrow becoming rather broad (0.25-0.4cm), equal or slightly wider in middle when old, 2 tiers of subgills, gills interveined at times; white to creamy white; edges even

Stem:
3-8cm x 0.1-0.25cm, equal, tubular, cartilaginous, not particularly fragile, somewhat elastic; white to pale yellow; bald above the base, pruinose toward the top, "when moist translucent and slightly transversely undulate or uneven"; base white-strigose or surrounded by matted white mycelium

Odor:
not distinctive

Taste:
not distinctive

Microscopic spores:
spores 7-9 x 3-4.5 microns, elliptic, inamyloid, [presumably smooth]; basidia 4-spored; pleurocystidia and cheilocystidia similar and abundant, 48-62 x 9-14(18) microns, "fusoid-ventricose with long, rather narrow necks", "the neck often incrusted with a mucilaginous substance, otherwise smooth, hyaline"; gill trama homogeneous, pale yellow in iodine; cap trama "with a thin, poorly differentiated pellicle, a somewhat differentiated hypoderm (most pronounced in old caps) and the remainder made up of somewhat enlarged cells and fairly compact, pale yellow in iodine"

Spore deposit:
white (Breitenbach)

Notes:
A. flavoalba has been found at least in WA, OR, ID, CO, MI, NC, and WY, (Smith), and Europe and North Africa, (Maas Geesteranus). There are collections from BC at the Pacific Forestry Centre.

EDIBILITY

Synonyms and Alternate Names:
Mycena flavoalba (Fr.) Quel.