Xerula rubrobrunnescens

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

Stalk growing into the ground like a root
Growing in woods

Cap brown or greyish brown; often slimy in wet weather; usually radially wrinkled or broadly striate
Stem white, sometimes with iridescent brown caulocystidia; fibrous, often visibly twisted
Gills white

Xerula rubrobrunnescens     Shoemaker, Ginns & Redhead