Collection location: Cabin Cove, Haywood Co., North Carolina, USA [Click for map]
avg-sized mushroom clustered on mossy well-rotted hardwood stump in moist hardwood forest, no odor
ST: curved, 60×3-4mm, somewhat broader below, tough, bending but not breaking, fairly solid, pale buff (not as yellow as cap), striate from innate fibers, discoloring brown from spores in age, white fuzz near base, flesh staining dark brown near edge when cut except near top
CAP: to 40mm wide, broadly convex, v faint small umbo, smooth, pale yellowish buff near margin to rich brown in center, marg v thin and minutely ragged
FLESH: to 2-3mm in center, pale yellowish, tough but flexible, not breaking
VEIL: partial, superior, skirt, v thin, membranous, brown (probably from spores)
GILL: attached, dirty yellowish-buff aging darker brown, not crowded or distant, straight, unbranched, brown spores visible as dusting at 20x
SPORE: print rich brown maybe a bit yellowish
Demystified keys this to either Galerina autumnalis or Agrocybe aegerita (thanks to the unremarkable “rich brown spore print”). These two mushrooms probably look nothing alike! With a microscope I could distinguish them: apparently Galerina has filamentous cuticle and roughened spores, Agrocybe has cellular cuticle and smooth spores.
Galerina autumnalis are rampant on every mossy stump in these woods these days, so it’s fairly clear this clump was probably just the first to come up.
The Agrocybe spores also should have a germ pore, if I remember correctly. Although there is a subsection of Galerina that has a germ pore, a very small one I think. But I forget if G. autumnalis is in that section.