Cap 2-4 cm broad, convex, expanding to plano-convex; margin at first incurved, then decurved; surface dry, matted tomentose at the disc, elsewhere fibrillose to finely scaled; color: dark purple at the disc, shading to vinaceous-purple at the margin, in age vinaceous-brown; context firm, thin, white, unchanging; odor when fresh, mild, when old, of fish; taste mild.
Gills free, close, white, unchanging.
Stipe 2-6.0 cm tall, 0.5-1.0 cm thick, stuffed, equal to tapering to enlarged, sometimes club-shaped base; surface pallid at the apex with patchy, flattened scales, tinged vinaceous-purple below from scattered appressed fibrils, unchanging when bruised; partial veil narrow, fibrillose-membranous, pallid on the upper surface, the lower surface and margin vinaceous-purple, forming a short, erect, superior annulus which may be sheathing above; stipe rooted in a dense white mycelium.
Spores 5.5-7 x 3.5-4.5 µm, elliptical, smooth, moderately thick-walled, dextrinoid; spore print whitish.
Solitary, scattered to clustered in duff of Monterey Cypress (Cupressus macrocarpa); fruiting from mid to late winter.
This attractive, diminutive Lepiota is distinctive with its vinaceous-purple, finely scaled cap and purple-tinged stipe. It can be fairly common in late winter under Monterey cypress, sometimes fruiting with two other Lepiotas, L. roseifolia and L. flammeatincta. These two species are distinguished by differently colored caps and color changes when bruised. In the case of Lepiota roseifolia, all parts redden when injured, while in Lepiota flammeatincta, only the gills remain white. Lepiota decorata is sometimes also confused with L. roseolivida, but according to Zeller's description, is much larger (pileus 6-12 cm broad), colored deep red/brown fading to a pinkish margin.
This taxa belongs in Leucoagaricus, but we are keeping it in Lepiota until a recombination of the names is published. (“Awaiting further research on tropical species, and the outcome of multigene phylogenetic analyses, Lepiota roseolivida and L. decorata are provisionally retained in the genus Lepiota, despite the fact that both species clearly do not belong there.”—Vellinga 2006.)