Leucocoprinus birnbaumii, also know as Flowerpot parasol is a bright yellow agaric that frequently occurs in greenhouses and flowerpots, especially with woody plants.
long and bell-shaped, expanding to convex or humped, with a smooth disc and easily detached powdery to fibrillose-granular scales that often becomes greyish brown. The surface under or between the scales is white to pale yellow. Gills
light yellow to white, thin, free from the stem, crowded and covered by a partial veil when young. Stem
narrowly bulbous or swollen at base, tapering to a very narrow apex, hollow. The surface is white and smooth. The ring is well developed but thin and easily detached.
include Leucocoprinus straminellus which is slightly paler (sometimes entirely whitish), Leucocoprinus flavescens which also is small-spored and has a yellowish cap with a brownish centre and Leucocoprinus sulphurellus which occurs in the Caribbean area, but has gills that bruise bright blue-green.
on the First Nature Web site.
on the MushroomExpert.Com Web site.
The third photo is by Ryan Van Gelder and licensed under the Creative Commons Attribution 3.0 Unported license.