World Library  
Flag as Inappropriate
Email this Article

Amanita onusta

Article Id: WHEBN0024883398
Reproduction Date:

Title: Amanita onusta  
Author: World Heritage Encyclopedia
Language: English
Subject: Amanita, List of Amanita species
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Amanita onusta

Scientific classification
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Amanitaceae[1]
Genus: Amanita
Species: A. onusta
Binomial name
Amanita onusta
(Howe) Sacc. (1891)
Synonyms[2]

Agaricus onustus Howe (1874)
Lepiota drymonia Morgan (1907)

Amanita onusta
View the Mycomorphbox template that generates the following list
Mycological characteristics
gills on hymenium

cap is convex

or flat
hymenium is free
stipe has a ring and volva
spore print is white
or mycorrhizal

edibility: poisonous

or unknown

Amanita onusta, commonly known as the loaded Lepidella or the gunpowder Lepidella, is a species of fungus in the Amanitaceae family of mushrooms. It is characterized by its small to medium-sized fruit bodies that have white to pale gray caps crowded with roughly conical, pyramidal, or irregular gray warts. The stem is whitish-gray with woolly or wart-like veil remnants, and at the base is a spindle- or turnip-shaped base that is rooted somewhat deeply in the soil. The species is distributed in eastern North America, from Nova Scotia to Mexico, and may be found growing on the ground in deciduous forests, particularly those with oak, hickory and chestnut. Fruit bodies smell somewhat like bleaching powder, and their edibility is unknown, but possibly toxic.

Taxonomy

Amanita onusta was first described in 1874 by American mycologist Elliot Calvin Howe as Agaricus onustus.[3] Later, in 1891, Pier Andrea Saccardo transferred the species to the genus Amanita.[4] Amanita authority Cornelis Bas, writing in his extensive 1969 monograph on the genus,[5] placed the species in his stirps Microlepis, subsection Solitariae, section Lepidellus.[6] This grouping of Amanita mushroom species also includes A. abrupta, A. atkinsoniana, A. costaricensis (a provisionally named species authored by Tulloss, Halling, & G.M. Muell.), A. nitida (as Coker[7] described the species) and A. sphaerobulbosa.[8]

The Latin epithet onustusa means "charged, load-carrying, burdened",[9][10] and a regular adjective derived from onus, "burden"[10] (the same word that gave the English onus).[11] A. onusta is commonly known as the "loaded Lepidella",[12] or the "gunpowder Lepidella".[13]

Description

The fruit bodies of Amanita onusta have caps that are initially broadly convex but flatten out as they mature, reaching diameters of 5 to 10 cm (2.0 to 3.9 in). The cap surface, grayish-white in color, is ornamented with conical or pyramidal raised warts, or flattened, symmetrically arranged gray to brownish gray, grayish brown or grayish-orange small scales (squamules) that are densely arranged over the surface.The squamules are less crowded near the edge of the cap (the margin). The margin does not have striations, and is typically fringed with remnants of the veil. The gills on the underside of the cap are spaced closely together, and either free or narrowly attached to the stem. They are white to cream color, and are interspersed with short lamellulae (gills that do not extend completely from cap margin to stem).[6] The gills may look as if they are waterlogged.[13]

The stem is 5.5 to 12 cm (2.2 to 4.7 in) long, 0.6 to 1.5 cm (0.2 to 0.6 in) thick, and tapers slightly upwards. It is solid gray to brownish-gray near base, paler towards the top, and appears cottony (floccose) or hairy (fibrillose). The bulb at the base of the stem is roughly spindle- to turnip-shaped, and may root deeply into the soil, especially if the soil is loose.[14] The short-lived partial veil is white, and attached just below the top of the stem. It is sticky and in maturity often clings to the upper part of the stem, or may have some meagre remnants hanging from the cap margin. The universal veil remains are arranged in rows of warts and patches of gray to brownish-gray small scales over the upper portion of the bulb; below this, the color is a dirty white. The flesh is firm and white.[6] Fruit bodies can range in smell from mild to "slightly unpleasant".[12] The odor has been described as resembling "chloride of lime",[15] a smell similar to some bathroom disinfectants containing bleach.[16]

Microscopic characteristics

Viewed in deposit, such as with a spore print, the spores are white. Viewed with a microscope, the spores are broadly ellipsoid to elongate, transclucent, thin-walled, amyloid, and have dimensions of 8.3–11.6 by 4.9–6.6 µm. The basidia (spore-bearing cells) are 38–46 by 9–11 µm, club-shaped, mostly 4-spored but some are 2- or 3- spored, with clamps. The cheilocystidia (cystidia found on the edge of a gill) are 23.3–31.5 by 11.6–15.7 µm, ellipsoid, club- to pear-shaped cells, partly in short rows. The cap cuticle is up to 168 µm thick, and consists of thin-walled interwoven hyphae that are 2–5.3 µm diameter, and gelatinized. Clamp connections are present in the hyphae of this species—these are short branches connecting one cell to the previous cell to allow passage of the products of nuclear division.[6]

Edibility

The edibility of A. onusta is unknown,[14] but the mushroom has been described as "possibly poisonous".[12] In general, species of Amanita are best avoided for consumption because of the prevalence of toxic species in that genus.[17]

Similar species

Amanita onusta may be confused with A. cinereoconia because of the similar gray powdery veil remnants on the cap surface.[12] A. cinereoconia is distinguished from A. onusta by the absence of clamps, its powdery-wooly to powdery-warty cap, as well as the absence of warts or scales at the base of the stem. A. cinereoconia also smells distinctly of chloride of lime.[12] Another similar species is A. costaricensis, found only in Costa Rica. A. atkinsoniana, another North American species, has shorter warts that are spaced further apart than those of A. onusta, and the warts on the basal bulb are arranged in parallel rows.[13]

Habitat and distribution

Amanita onusta grows solitary or scattered on the ground in mixed oak, hickory and chestnut forests from southern New England to Texas.[6] The species has a preference for sandy or loose soils.[18][19] Its range extends north to Nova Scotia, Canada,[20] and south to Mexico.[21]

See also

Fungi portal

References

Cited books

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.