Major Groups > Gilled Mushrooms > Pale-Spored > Lepiota & Satellite Genera > Leucocoprinus birnbaumii


Leucocoprinus birnbaumii

[ Basidiomycetes > Agaricales > Agaricaceae > Leucocoprinus . . . ]

Taxonomy in Transition: ...  > Agaricales > Lepiotoid Clade (J&V, 1998)

by Michael Kuo

This little yellow mushroom is the subject of many frantic e-mails to MushroomExpert.Com, since it has a tendency to pop up unexpectedly in people's flower pots--even indoors!

Leucocoprinus birnbaumii won't hurt you, unless you eat it. It won't hurt your plant. It won't hurt your pets or your children, unless they eat it. There is no getting rid of it, short of replacing all the soil in your planter (and even then it might reappear). Since it makes such a beautiful addition to your household flora, I recommend learning to love it--and teaching your children to love it, too.

You might also impart the idea that mushrooms are very, very cool--but shouldn't be eaten. Perhaps your child would like to become an awesome and famous mycologist some day. I would love to encourage your child's interest in mushrooms by putting his or her drawing of Leucocoprinus birnbaumii on this Web page (at least temporarily). Here's a drawing from 8-year-old Daniel in Queensland:

Leucocoprinus birnbaumii


Ecology: Saprobic; growing alone, gregariously, or clustered in flower pots, greenhouses, and so on--or, in warm conditions, outside in gardens and other cultivated areas (often around stumps); also growing in hardwood and conifer forests, especially in disturbed ground areas (pathsides, etc.); outdoors in summer, indoors year-round; widely distributed in North America.

Cap: 2.5-6 cm, oval when young, becoming broadly conical or bell-shaped; dry; powdery to scaly; the margin lined or grooved nearly to the center; bright to pale yellow, often with a darker center.

Gills: Free from the stem; yellow to pale yellow; crowded.

Stem: 3-10 cm long; 1-5 mm thick; more or less equal, or tapering to apex; dry; smooth or powdery; with a fragile, yellow ring that often disappears.

Flesh: Yellow throughout; very thin.

Odor and Taste: Odor not distinctive; taste mild or bitter.

Spore Print: White.

Microscopic Features: Spores 8-13 x 5.5-8 µ; smooth; elliptical; dextrinoid; thick-walled; with a small pore. Basidioles inflated, brachybasidiole-like. Cheilocystidia to about 65 x 15 µ; ventricose or irregular, often with fingerlike projections. Pleurocystidia absent.

REFERENCES: (Corda, 1839) Singer, 1962. (Bolton, 1788 [text, illustration]; Saccardo, 1912; H. V. Smith, 1954; Smith, Smith & Weber, 1979; H. V. Smith, 1981; H. V. Smith & Weber, 1982; Weber & Smith, 1985; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Metzler & Metzler, 1992; Horn, Kay & Abel, 1993; Barron, 1999; McNeil, 2007.)

Lepiota lutea is a synonym, as are Leucocoprinus luteus, Leucocoprinus flos-sulfuris, and Lepiota cepaestipes var. luteus. There are several closely related species, including Leucocoprinus flavescens (with a brownish cap center and smaller spores) and Lepiota fragilissimus, with an extremely thin cap and pale gills. Leucocoprinus cepaestipes has a white or pinkish cap, and smaller spores.

Further Online Information:

Leucocoprinus birnbaumii at MykoWeb
Leucocoprinus birnbaumii at Agaricales of the Hawaiian Islands
Leucocoprinus flos-sulfuris at Roger's Mushrooms


The photos below were sent in by MushroomExpert.Com readers whose flower pots produced Leucocoprinus birnbaumii:

Leucocoprinus birnbaumii

Leucocoprinus birnbaumii

Leucocoprinus birnbaumii

Leucocoprinus birnbaumii

Leucocoprinus birnbaumii

Leucocoprinus birnbaumii

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Cite this page as:

Kuo, M. (2007, October). Leucocoprinus birnbaumii. Retrieved from the MushroomExpert.Com Web site: