Galerina autumnalis

Scientific name:  Galerina autumnalis (Peck) A.H. Sm. &
Singer
Derivation of name: Autumnalis implies being found during
the fall. 
Synonyms:  Pholiota autumnalis Peck
Common name(s):  Deadly Galerina.
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Cortinariaceae
Occurrence on wood substrate:  Saprobic; in small groups or
clusters on decaying deciduous and conifer wood such as logs,
stumps, and buried wood; May through June, October through
November.  
Dimensions:  Caps 2.5-6.5 cm wide; stipes 2.5-10 cm long
and 0.3-1 cm thick.   
Cap:  Sticky, smooth, yellow-brown to dark brown.        
Gills: Attached; yellowish, becoming rust colored. 
Spore print: Rusty brown.
Stipe: Whitish above, browish toward base; whitish mycelium
at point of attachment.
Veil: Membranous, white, evanescent. Appearing brown from
spore deposit.
Edibility: Deadly poisonous.
Comments: This mushroom contains the deadly phallotoxins
and amatoxins, reason enough to avoid all little brown
mushrooms on wood.
.   
More information at MushroomExpert.com:
More information at TomVolkFungi.net:

Figure 1. Deadly Galerina on a moss-covered log. Note
the veils, overall brownish color, and shiny (sticky) cap.
Photo © William Roody.

Figure 2. Mushroomers often ignore "little brown
mushrooms" due to their reputation as being difficult to
identify. Because of its deadly toxins, there is reason to
have a good mental image of this particular little brown
mushroom. Photo © Larry Grand.