Species Fact Sheet
Common Name: American prairie Lepidella
Scientific Name: Amanita prairiicola Peck (= Amanita malheurensis Trueblood, O.K.
Mill. & D.T. Jenkins)
Division: Eumycota
Subdivision: Basidiomycotina
Class: Hymenomycetes
Order: Agaricales
Family: Amanitaceae
Type Locality: Malheur Co., Oregon.
Holotype: VPI 24127
Technical Description:
Cap 5-11 cm wide, thin to thick, convex to nearly plane when older; margin slightly
incurved, non-striate, appendiculate, with a distinct sterile edge, occasionally with radial
splits; surface tissue of cap membranous, easily separated from underlying tissue,
glabrous, dry to slightly sticky when moist; off-white with tannish disc, or pale tannish
overall; flesh white, unchanging, up to 15 mm thick on disc, tapering to margin; universal
veil remnants as low, irregular warts or patches, becoming flocculose toward margin,
randomly distributed, white to occasionally light brownish. Gills moderately crowded,
free, arcuate, edges slightly flocculose, off-white to slightly creamy when young, grayish
at maturity, drying yellowish to orange. Stalk 5-7(-15) cm x 20-35 mm, tapering toward
base, nearly glabrous at apex, fibrillose to fibrous below annulus, white, but becoming
yellowish to light reddish-brown where handled, solid to pithy in center, no distinct basal
bulb; universal veil remnants as squamules or patches, randomly distributed or near
concentric rings, white. Partial Veil (annulus) white, on upper or mid-portion of stalk,
thin, membranous, pendant initially, but frequently breaking apart, protions frequently
adhering to cap margin. Spores 10.1-13.3 x 5.5-8.6 um, elongate, adaxially flattened,
thin-walled, hyaline, very weakly amyloid; spore print white. Other: Basidiocarps small
to medium, gregarious; without distinct taste, but odor earthlike to medicinal or
antiseptic.
Any mushroom with a universal veil, pallid (very pale colored) gills and white spores is
likely to be an Amanita. There are several white-spored, annulus-bearing mushroom
genera that might be mistaken for Amanita. Species of Lepiota generally lack a
universal veil and its associated volva. Species of Armillaria and Cystoderma generally
lack a universal veil/volva as well, and in addition, most have attached gills.
Amanita prairiicola resembles A. armillariiformis in features such as 1) xeric, nonforested habitats, 2) sterile edge on cap margin that is frequently appendiculate, 3)
essentially cylindric stalk with indistinct bulb, 4) medicinal odor (not in all specimens),
and 5) elongate spores (elliptical to elongate in A. armillariiformis). In contrast, caps of
Amanita armillariiformis are typically dull white to pinkish-buff, with pale salmon
universal veil patches, with surface tissue thin, slightly gelatinized, not easily separated
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from underlying tissue, and gills pale tan at maturity. Caps of A. prairiicola are typically
pale tan with brownish universal veil patches, with surface tissue membranous and easily
separated from underlying tissue, and gills grayish at maturity.
Life History
Basidiocarps are produced from late April through June. Sporocarps are gregarious at
known sites.
Range, Distribution and Abundance
Amanita prairiicola is known from Arizona to eastern Oregon and eastward to Kansas
(where it was first described). In eastern Oregon, it is known only from Malheur Co,
where seven sites are documented between Vale and Leslie Gulch, about 44 miles south
of Vale. One specimen is known from a planted area in Argentina, but it may have been
imported with soil.
Habitat Associations
This is a species of tall grass prairie and high elevation desert. It is frequently fround
with no nearby woody plant symbiont. It has been found in desert with no living plant in
its vicinity. In eastern Oregon it is known from desert areas with sand dunes and desert
range land with cattle grazing, near or under Artemisia, Sarcobatus vermiculatus,
Chrysothamnus nauseosus and in association with Myosurus aristata. Amanita
malheurensis is assumed to be ectomycorrhizal.
Threats: The ecology of ectomycorrhizal fungi inhabiting xeric plant communities east
of the Cascades in Oregon and Washington appears to be a much less studied than that of
fungi of the mesic and damper coniferous forests in and west of the Cascades. Threats
that generally apply to this latter group of fungi may not necessarily be transferable to the
former group. Nevertheless, while awaiting the development of more relevant data, it is
reasonable to assume that actions or events that remove host plants and/or reduce cover
of coarse woody debris or other organic nutrient sources may have detrimental effects to
Amanita. Reduction in various ground covers that promote retention of soil moisture
may also adversely effect this fungus.
Conservation Considerations: Revisit documented localities to reconfirm presence and
better define habitat. Monitor known sites to better understand relationship between
sporocarp production and environmental variables. Consider mapping areas with high
potential for suitable habitat. Search for new populations on federal land. Consider
buffering known sites and protecting from wildfire, prescribed burns, vegetation
management projects that would remove potential host plants, and ground-disturbing
activities (e.g., recreational vehicles, grazing) that would reduce moisture-retaining
ground covers. Support research focusing on the ecology of dryland fungi, including the
effects of invasive plant species.
Conservation Rankings and Status:
Global: G3?; Oregon S1
ORNHIC List 3
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Prepared by: Rick Dewey, Deschutes National Forest, March 2009
References
Arora, David. 1979. Mushrooms Demystified - A Comprehensive Guide to the Fleshy
Fungi. Ten Speed Press, Berkeley, California. 959 pp.
Cushman, Kathleen and Rob Huff. 2007. Conservation Assessment for Fungi Included
in Forest Service Regions 5 and 6 Sensitive and BLM California, Oregon and
Washington Special Status Species Programs. R6 USFS and OR/WA BLM Interagency
Special Status/Sensitive Species Program (ISSSSP).
http://www.fs.fed.us/r6/sfpnw/issssp/planning-tools/
Ferriel, Jenifer and Katie Grenier. 2008. Annotated Bibliography of Information
Potentially Pertaining to Management of Rare Fungi on the Special Status Species List
for California, Oregon and Washington. R6 USFS and OR/WA BLM Interagency
Special Status/Sensitive Species Program (ISSSSP).
http://www.fs.fed.us/r6/sfpnw/issssp/planning-tools/
Fogel, Robert. 1994. Report on Fungi from the Columbia Basin Deposited in the
University of Michigan Herbarium. Interior Columbia Basin Ecosystem Management
Project, Science Integration Team - Terrestrial Staff. December 7, 1994. 21 pp. + 5
appendices.
Lindgren, Janet. 1998. Trial key to the species of Amanita in the Pacific Northwest.
Prepared for the Pacific Northwest Key Council. (includes A. armillariiformis)
http://www.svims.ca/council/Amanit.htm
Miller, Orson K. Jr., Ellen Trueblood and David T. Jenkins. 1990. Three new species of
Amanita from southwestern Idaho and southeastern Oregon. Mycologia, 82(1), pp. 120128.
Oregon Natural Heritage Information Center. 2007. Rare, threatened and endangered
species of Oregon. Oregon Natural Heritage Information Center, Oregon State
University. Portland. 100pp.
http://oregonstate.edu/ornhic/2007_t&e_book.pdf
Tulloss, Rodham and Zhu-liang Yang (Eds.). 2009. Studies in the Genus Amanita Pers.
(Agaricales, Fungi).
http://njcc.com/~ret/amanita/mainaman.html
USDA Forest Service. 1995. Report on Fungi. Prepared by Michael A. Castellano for
Interior Columbia Basin Ecosystem Management Project.
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