Laccaria trullisata

This is a key to gilled mushrooms, that is, mushrooms having a definite cap with a fertile surface consisting of gills. The fruiting body usually also has a stem, although that may be lateral or absent (usually, then, the mushroom is growing from wood). You can use this key to identify mushrooms that you find.

Fruiting body containing fibers (usually in the stalk)

Spore print "light-colored": white or buff, sometimes tinged with pink or tan. Greenish and (except for the Russulales) yellow spore prints also go here
Stalk fibrous, not fracturing like a piece of chalk

None of the special features distinguishing the other white-spored genera:
Gills not free, as in the Lepiotas and Amanitas
Basidia not extra-long, as in the Hygrophoraceae
Spores smooth, except for Lentinellus

Growing on the ground

Found in woods
Not rooting

Gills attached to decurrent
Coloration usually white to greyish brown, sometimes purple or with purple tones
Never with a ring of any kind

Fruiting body often with purple colors, especially on the gills
If no purple colors, then cap warm brown and minutely scaly, and gills white
Base of stalk (sometimes entire stalk) coated with fuzzy white or purple mycelium
Stalk often with tough "shavings" or "hangnails" of fibrous tissue projecting from it

Laccaria trullisata     (Ellis) Peck