According to Kew Species Profiles[KSP]
Kew Species Profiles
- General Description
The aptly named 'plantpot dapperling' mushroom often provides a surprise when its brilliant yellow fruiting bodies spring suddenly but fleetingly from plant pots in the dead of winter.
Leucocoprinus birnbaumii is an attractive, brightly coloured tropical mushroom that grows in rich soils. First described by the Czech mycologist August Corda in 1839, it is perhaps best known for its spontaneous appearance in indoor plant pots and greenhouses throughout the world. In fact, L. birnbaumii was first discovered growing on and between pineapple plants in a German earl’s garden. Its name ‘ birnbaumii’ refers to Birnbaum, the earl’s Garden Inspector.
Because it recycles dead organic material, this mushroom does no harm to its horticultural neighbours, and its burst of brilliance can thus be appreciated guilt-free!
- Species Profile
Geography and distribution
Worldwide, in both natural and horticultural habitats.
Plantpot dapperling is a universally sulphur-yellow gilled mushroom that is easy to identify because of its bright colours and preferred habitat in houseplant pots, greenhouses and gardens.
The cap can be up to 7 cm across, but is usually smaller (2−4 cm). It is conical at first, but expands to become more or less flat; it can sometimes have a central knob or be indented. The surface is often finely roughened.
Underneath the cap, widely spaced yellow gills radiate from the centre. When mushrooms are young, the gills are covered by a thin yellow skin that stretches from the edge of the cap to the stalk, but this skin soon tears from the cap and can remain on the stalk like an inverted skirt. The stalk is up to 10 cm tall, but is typically shorter (5−7 cm) and slightly swollen at the base. The spores appear white in mass but are colourless and smooth under the microscope.
One variety (L . birnbaumiivar. salvadorianus) has been recognised from Brazil, which differs in a scalier cap with a brick-coloured centre.
Just the one?
This species is easily recognised by its bright colour and habit of growing in pots and greenhouses worldwide. Its large range of spore sizes and numerous synonyms suggest there may actually be several species included under the name Leucocoprinus birnbaumii.
To eat or not to eat?
Plantpot dapperling is poisonous, but people and pets rarely try to eat it – it is possible its bright colour provides an instinctive warning. Its yellow pigments are due to chemicals called novel alkaloids, birnbaumins A and B. Although alkaloids are often toxic, it is not known if birnaumins are the active poisons in this mushroom.
Unexpectedly, Leucocoprinus birnbaumii is closely related to the preferred food of certain neotropical fungus-farming ants, which cultivate a closely related species. Did the ants choose to farm these fungi just because they are abundant in tropical soils, or because they are easy to cultivate in a variety of circumstances? Perhaps the adaptability of the plantpot dapperling to habitats around the world offers a clue. Their ability to thrive in artificial habitats is evidence of their adaptability to a wide variety of conditions.
This species at Kew
This species occurs spontaneously in greenhouses and flowerpots throughout Kew.
- Rich soils in tropical and subtropical regions; also common in plant pots and greenhouses in temperate regions.
- Widespread and common.
Poisonous, causing gastrointestinal irritation.
- Plantpot dapperling
First published in Sydowia 15(1-6): 67 (1962) 
-  Bartsch, A., Bross, M., Spiteller, P., Spiteller, M. & Steglich, W. (2005). Birnbaumin A and B: Two unusual 1-hydroxyindole pigments from the “flower pot parasol” Leucocoprinus birnbaumii. Angewandte Chemie International Edition, 44: 2957–2959.
-  Breitenbach J. & Kränzlin, F. 1995. Fungi of Switzerland Vol. 4, Agarics 2nd part. Edition Mykologia Lucerne, Switzerland.
-  Raithelhuber, J. 1987. Die gattung Leucocoprinus Pat. in den ABC-Staaten. Metrodiana 15:5-17.
-  Ammirati, J. F., Traquair, J. A. & Horgen, P. A . (1985) Poisonous Mushrooms of the Northern United States and Canada. University of Minnesota Press, Minneapolis.
-  Corda, AKJ. 1839. Icones fungorum hucusque cognitorum, Vol III. Prague : apud J. G. Calve, 1837-54.
Index Fungorum (2016). Published on the Internet http://www.indexfungorum.org
[A] © Copyright 2016 Index Fungorum Partnership. https://creativecommons.org/licenses/by/3.0
Kew Species Profiles
Kew Species Profiles