Summary:
Features include 1) a whitish umbonate cap that is tinged yellowish or pale brown in the center and is finely scaly-fibrous at the margin, 2) a white stem that is at first woolly-cottony below the ring, 3) a white spore deposit, and 4) large spindle-shaped spores. The online Species Fungorum, accessed April 3, 2016, gave this taxon as a synonym of Lepiota erminea (Fr.) P. Kumm., which Moser(1) and Hansen, L.(2) differentiate by its radish taste among other characters.

Cap:
3-5(8)cm across, bell-shaped becoming convex to flat, with obtuse umbo and acute margin; white to cream-white, pale brownish in center; finely fibrillose-tomentose to woolly-scaly in places, margin finely fimbriate-fibrillose [fringed], (Breitenbach), up to 7cm across, white, umbo sometimes a bit brown; smooth, sometimes a few scales on the margin, (Schalkwijk-Barendsen), 3-6cm across, broadly umbonate; whitish, disc with yellow tinge; at first smooth then flocculose, (Hansen), 3-6(8)cm across, umbonate; white, center light yellowish; finely scaly-fibrous at margin, (Moser)

Flesh:
thin; white, (Breitenbach), white, (Schalkwijk-Barendsen)

Gills:
free, 35-43 reaching stem, broad, 1-3 subgills between each pair of gills; white to cream; edges smooth to white-flocculose, (Breitenbach), close when young, distant when mature, sometimes forking, broad; white, (Schalkwijk-Barendsen)

Stem:
4-6(8)cm x 0.4-0.7cm, cylindric, rigid, fragile, hollow; "surface above the annular zone smooth, whitish, slightly white-floccose, surface below white peronate-floccose on a brownish background", (Breitenbach), up to 6cm long and up to 0.6cm wide, equal, hollow; white; sometimes woolly below ring, (Schalkwijk-Barendsen), 4-6cm x 0.3-0.5cm, white; "at first cottony below distinct ring, then smooth", (Hansen), 4-6cm x 0.3-0.5cm, woolly-booted-ringed, (Moser)

Veil:
ring white, floccose-fibrillose, fugacious [fleeting], (Breitenbach), small ring, woolly at first, later just a remnant, more delicate than in Lepiota clypeolaria, (Schalkwijk-Barendsen)

Odor:
like Lepiota cristata, (Breitenbach), no radish odor (Moser)

Taste:
mild, rather unpleasant, (Breitenbach), no radish taste (Hansen, Moser)

Microscopic spores:
spores 10.4-16.4 x 4.9-6.8 microns, elliptic to navicular [boat-shaped], smooth, dextrinoid; basidia (2-)4-spored, 35-45 x 10-12 microns, clavate, with basal clamp connection; pleurocystidia not seen, cheilocystidia 21-32 x 8-15 microns, clavate; cap cuticle of prostrate hyphae in part with erect ends 50-200 x 5-12 microns, interspersed basally with clavate to cylindric cells, colorless to brownish-pigmented; clamp connections mentioned for basidia and cap cuticle, (Breitenbach), spores 11-14 x 5.5-6.5 microns, fusoid [somewhat spindle-shaped], cheilocystidia 17-25 x 8-9 microns, clavate, (Hansen), spores 12-14 x 5.5-6.5 microns, spindle-shaped, (Moser)

Spore deposit:
cream-yellow (Breitenbach), white (Schalkwijk-Barendsen)

Notes:
Lepiota alba (Bres.) Sacc. was reported by Schalkwijk-Barendsen(1) for Kamloops BC, and there is collection from BC at the University of British Columbia. It has been reported from WA by Andrew Parker (pers. comm.).

EDIBILITY

not recommended (Schalkwijk-Barendsen)

Synonyms and Alternate Names:
Lepiota clypeolaria var. alba Bres.
Lepiota clypeolaria var. alba Bres.