Summary:
Sacchariferae (Maas Geesteranus), Smith places in Subgenus Pseudomycena (characterized by a bulb or disc at the stem base) Section Tenerrimae (coarsely granular under a hand lens due to warty round cells). Mycena tenerrima is characterized by small size, a pale gray or gray brown cap that is whitish toward the margin, a short stem with a cushion-like disc at base, cheilocystidia, and warty cells on the cap that give it a sugary appearance under a hand lens. Smith(1) said it is "not uncommon along the Pacific Coast". Mycena adscendens was listed as a synonym in the online Species Fungorum, accessed October 14, 2018, but MycoBank, accessed the same day, listed them separately.

Gills:
narrowly adnate, seceding but adhering to each other and becoming collar-like, ascending, moderately ventricose [broader in middle], up to 0.05cm broad, 7-12(14?) reaching stem; white; fringed, (Maas Geesteranus), free or attached to stem by a line, distant, broad, sometimes adhering to each other and forming a slight collar around stem; white, (Smith)

Stem:
0.5-1(1.8)cm x 0.01-0.04cm, widening toward base, fragile, hollow; white, becoming yellowish in lower part when old; shiny, minutely puberulous [finely downy] throughout or bald in upper part and hirsute [hairy] further down, finely striate, springing from densely hairy and cushion-like white disc, (Maas Geesteranus) 0.5-1.5(2)cm long, usually curved and thread-like; hyaline white; base enlarged with slight bulb that is globular at first but becomes flattened, setose under a lens at first but when old merely pruinose over all, including bulb

Odor:
none (Maas Geesteranus)

Taste:
mild (Buczacki)

Microscopic spores:
spores 8.1-9.6 x 5.4-5.8 microns, pip-shaped, smooth, amyloid; basidia 2-spored (rarely 1-spored), 14-17 x 7-9 microns, clavate, obpyriform, with clamp connections; pleurocystidia none, cheilocystidia 13.5-36 x 4.5-10 microns, "either clavate or obpyriform to subglobose, or lageniform to fusiform with a slender neck" 1.8-2.7 microns wide, clamped, smooth to more or less covered with warts or cylindric excrescences up to 6.3 microns long, "intermediate forms of the two types being common and occurring in all shapes", (Maas Geesteranus), spores 8-10 x 5-6.5(7) microns, broadly elliptic, amyloid; basidia 2-spored; pleurocystidia "rare or absent, if present similar to the cheilocystidia"; cheilocystidia abundant, 28-44 x 8-12 microns, variable in shape, often fusoid-ventricose or with 2-3 needle-like projections arising from tip, the projections forked at times, the ventricose part covered with short rod-like protuberances or merely verrucose; cap trama made up of greatly enlarged cells, the surface covered with clavate to almost spherical cells 25-40 x 20 microns, with finely verrucose walls, (Smith)

Spore deposit:
whitish (Breitenbach quoting literature)

Notes:
Mycena tenerrima has been found at least in WA to CA, and also in Europe including Denmark, (Smith), the Netherlands (Maas Geesteranus), and Switzerland (Breitenbach). There is a voucher and photograph from BC by Oluna Ceska.

EDIBILITY

Synonyms and Alternate Names:
Mycena adscendens Maas Geest.