Lepiota

''Lepiota'' is a genus of gilled mushrooms in the family Agaricaceae. All ''Lepiota'' species are ground-dwelling saprotrophs with a preference for rich, calcareous soils. Basidiocarps (fruit bodies) are agaricoid with whitish spores, typically with scaly caps and a ring on the stipe. Around 400 species of ''Lepiota'' are currently recognized worldwide. Many species are poisonous, some lethally so.

Taxonomy

History

''Agaricus'' section ''Lepiota'' was originally published in 1797 by South African-born mycologist Christian Hendrik Persoon. It was subsequently raised to the rank of genus by Samuel Frederick Gray. As originally conceived, the genus was a mix of agarics with rings on their stems, including species now placed in '' Armillaria'', '' Cortinarius'', and '' Pholiota''. In 1822, however, the influential Swedish mycologist Elias Magnus Fries restricted ''Lepiota'' to white-spored, ringed agarics.

Based on macro- and micromorphology, later authors gradually refined the generic concept of ''Lepiota''. Some unrelated genera, such as '' Cystoderma'' ( Fayod 1889) and '' Limacella'' ( Earle 1909), were removed from the genus whilst several related genera, including '' Leucocoprinus'' ( Patouillard 1888), '' Macrolepiota'' and '' Leucoagaricus'' ( Singer 1948), '' Cystolepiota'' (Singer 1952), and '' Echinoderma'' (Bon 1991) were separated off. These segregated genera, together with ''Lepiota'' itself, are still often grouped together as ''Lepiota s.l.'' ('' sensu lato'' = "in the wide sense") or as the "lepiotoid" fungi.

The secotioid species ''Amogaster viridiglebus'', described in 1996 and initially placed in the order Boletales, was later determined to be a member of ''Lepiota'', and officially transferred to the genus in 2013.

Current status

Following some discussion over the type species, ''Lepiota'' has now been conserved under the International Code of Nomenclature for algae, fungi, and plants, typified by ''Agaricus colubrinus'' Pers. (= '' Lepiota clypeolaria''). Recent molecular research, based on cladistic analysis of DNA sequences, suggests that the morphological concept of ''Lepiota s.s.'' (''sensu stricto'' = in the strict or narrow sense) is soundly based.

The name "Lepiota" is derived from the Greek λεπις (= "scale") + οὖς (= "ear").

Description

Fruit bodies of ''Lepiota'' species are almost all agaricoid ('' Lepiota viridigleba'' is the sole sequestrate species in the genus), most (but not all) having comparatively small caps (less than in diameter) and slender stems. The cap cuticle (surface skin) typically splits as the cap expands, breaking up into concentric rings of scales towards the margin. The gills beneath the cap are white to cream (rarely yellow) and are free (not joined to the stem). The gills are covered by a partial veil when young, which typically ruptures to leave a cuff-like ring (sometimes ephemeral) often with additional scaly remains on the stem. Several species have a distinct, often rubbery, smell. The spore print is white to cream. The spores are usually (but not always) dextrinoid (turning red-brown in an iodine-based reagent).

Habitat and distribution

Most if not all ''Lepiota'' species are nitrophilic, with a preference for calcareous soils. They typically occur in rich humus in broadleaf or conifer woodland, in northern Europe often among nettles ('' Urtica dioica'') or dog's mercury ('' Mercurialis perennis''). A few species are more frequently found in calcareous grassland or in dunes. The genus has a cosmopolitan distribution, but with a preference for warm areas, meaning there are fewer species in colder climates. Around 400 species are currently recognized worldwide.

Toxicity

Several species contain amatoxins and are lethally poisonous, if consumed. Those known to have caused fatalities include '' Lepiota brunneoincarnata'', '' L. brunneolilacea'', '' L. castanea'', '' L. helveola'', and '' L. subincarnata'' (synonym ''L. josserandii''). No ''Lepiota'' species is recommended as edible.

Literature

No comprehensive monograph of the genus has yet been published. In Europe, however, species of ''Lepiota'' were illustrated and described in a regional guide by Candusso & Lanzoni (1990) and more briefly in descriptive keys by Bon (1993). Dutch species were illustrated and described by Vellinga (2001). No equivalent modern guides have been published for North America, but Vellinga (2008) has published an online bibliography of the relevant literature. In Australia, a guide to the ''Lepiota'' species of south-eastern Queensland was published by Aberdeen (1992). In Asia, a study of ''Lepiota'' diversity in northern Thailand revealed 73 species.

File:Lepiota subincarnata 117620.jpg,
File:Lepiota magnispora 39264.jpg,
File:Lepiota castanea 70848.jpg,
File:Lepiota cristata 20070819w.jpg,
File:Lepiota_castaneidisca_AlanRockefeller.JPG,
File:Lepiota lilacea.jpg,

List of species

The following species have individual entries:
*'' Lepiota ananya''
*'' Lepiota anupama''
*'' Lepiota babruka''
*'' Lepiota babruzalka''
*'' Lepiota bengalensis''
*'' Lepiota brunneoincarnata''
*'' Lepiota castanea''
*'' Lepiota clypeolaria''
*'' Lepiota harithaka''
*'' Lepiota helveola''
*'' Lepiota ignivolvata''
*'' Lepiota nirupama''
*'' Lepiota shveta''
*'' Lepiota spheniscispora''
*'' Lepiota subincarnata'' (synonym ''L. josserandii'')
*'' Lepiota zalkavritha''
*'' Lepiota locanianisis'' † (extinct)

The following species have individual entries, but are now placed in different genera:

*''Lepiota aspera'' = '' Echinoderma asperum''
*''Lepiota lutea'' = '' Leucocoprinus birnbaumii''
*''Lepiota molybdites'' = '' Chlorophyllum molybdites''
*''Lepiota naucina'' = '' Leucoagaricus leucothites''
*''Lepiota procera'' = '' Macrolepiota procera''
*''Lepiota rhacodes'' = '' Chlorophyllum rhacodes''

See also

* List of Agaricaceae genera
* List of Agaricales genera

References

{{Authority control

Agaricales genera
Taxa named by Christiaan Hendrik Persoon