Summary:
{See also Hemimycena Table.} Hemimycena delectabilis is characterized by small size, white color, obtuse cap, nitrous odor (bleach-like), small moderately broad spores, and cystidia on both the faces and the edges of the gills. Smith(1) gives Agaricus delectabilis Peck, Prunulus leucophaeus Murrill, and Mycena leucophaea Murrill as synonyms but Redhead(15) later gives Prunulus leucophaeus Murrill and Agaricus delectabilis Peck as synonyms of Helotium leucophaeum (Murrill) Redhead. Still later, Redhead(5) mentions reports from BC of both Hemimycena delectabilis and Hemimycena leucophaea, the latter as a new combination and referring to Redhead(15).

Cap:
(0.3)0.8-2cm across, obtusely conic with appressed margin at first, sometimes bell-shaped, becoming broadly conic to broadly bell-shaped, sometimes papillate; "watery white at first or the disc with a faint watery-gray cast, almost chalk white when faded or in age a bit yellowish around the disc", (Smith)

Flesh:
thin, fragile; white, (Smith)

Gills:
arcuate becoming long decurrent, subdistant to distant, narrow; white; edges even or fimbriate [fringed], (Smith)

Stem:
2-4cm x 0.05-0.15(0.2)cm, nearly filiform [thread-like] at times, fragile-cartilaginous, tubular; white; bald except for the base being white strigose and top faintly pruinose, (Smith)

Odor:
strong nitrous, sometimes evident only if flesh crushed, or absent, (Smith), strong, unpleasant, acrid, (Buczacki)

Taste:
"hardly distinctive" (Smith)

Microscopic spores:
spores 5-7 x 3.5-4 microns, subelliptic [more or less elliptic], smooth, inamyloid; basidia 4-spored; pleurocystidia scattered to abundant, 33-58 x 7-12 microns, fusoid-ventricose [spindle-shaped - wider in the middle], elongating to subcylindric [somewhat cylindric] or nearly filamentous at times, cheilocystidia similar and numerous, (Smith)

Spore deposit:
white (Buczacki)

Notes:
Hemimycena delectabilis has been found in WA, OR, ID, NS, ON, CA, and NY, and is not uncommon during late summer and fall in wet weather, (Smith), but note that these collections could include some collections of Hemimycena leucophaea according to the Smith concept. Hemimycena delectabilis has been found in BC (reported in Redhead(5) and there is a collection from BC at the University of British Columbia). There is a collection from AK at the University of Washington.

EDIBILITY

Synonyms and Alternate Names:
Mycena delectabilis (Peck) Sacc.