Veined Mossear

Rimbachia bryophila

Pileus
Cap 5.0-10.0 mm long by 5.0-7.0 mm wide, pendulous cupulate, then pleurotoid to broadly fan-shaped; margin incurved, decurved in age, sometimes wavy; surface whitish, sparsely pubescent near the base, elsewhere glabrous or matted-fibrillose when dry; context very thin, less than 1 mm, watery-white; odor and taste mild.

Hymenophore
Hymenium nearly smooth at first, soon developing gill-like folds radiating from a basal attachment point, subdistant, eventually wavy to contorted and intervenose; whitish at all stages.

Stipe
Stipe absent to greatly reduced, fruiting body eccentric or lateral in attachment.

Spores
Spores 5.0-6.5 x 4.5-6.0 µm, hyaline in water, inamyloid, subglobose to broadly tear-shaped, smooth, thin-walled, hilar appendage conspicuous, up to 2.0 microns long, contents granular; spore print not seen.
Rimbachia bryophila I knew if I looked at enough tiny white mushrooms on mosses, I'd eventually find one of the other species ;p Fall,Geotagged,Rimbachia bryophila,United States

Appearance

Pileus
Cap 5.0-10.0 mm long by 5.0-7.0 mm wide, pendulous cupulate, then pleurotoid to broadly fan-shaped; margin incurved, decurved in age, sometimes wavy; surface whitish, sparsely pubescent near the base, elsewhere glabrous or matted-fibrillose when dry; context very thin, less than 1 mm, watery-white; odor and taste mild.

Hymenophore
Hymenium nearly smooth at first, soon developing gill-like folds radiating from a basal attachment point, subdistant, eventually wavy to contorted and intervenose; whitish at all stages.

Stipe
Stipe absent to greatly reduced, fruiting body eccentric or lateral in attachment.

Spores
Spores 5.0-6.5 x 4.5-6.0 µm, hyaline in water, inamyloid, subglobose to broadly tear-shaped, smooth, thin-walled, hilar appendage conspicuous, up to 2.0 microns long, contents granular; spore print not seen.

Naming

Mniopetalum bryophilum

Habitat

Scattered to gregarious on moss-covered banks; fruiting from mid to late winter.

References:

Some text fragments are auto parsed from Wikipedia.

https://www.mykoweb.com/CAF/species/Rimbachia_bryophila.html
Taxonomy
KingdomFungi
DivisionBasidiomycota
ClassAgaricomycetes
OrderAgaricales
FamilyTricholomataceae
GenusRimbachia
SpeciesRimbachia bryophila