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Lepiota aspera [ Basidiomycetes > Agaricales > Agaricaceae > Lepiota . . . ]
by Michael Kuo In my area (central Illinois), Lepiota aspera appears in oak-hickory woods in late summer and fall. It closely mimics the appearance of an Amanita, but lacks the distinctive stem base common to many Amanita species. Crucial identification characters for Lepiota aspera include the orangish brown cap that develops sharp little scales; the flimsy but somewhat persistent ring on the stem, which often has an underside decorated with scales like those on the cap; and microscopic features (see below). Lepiota aspera is featured as "Lepiota acutesquamosa" in most North American field guides. Although it is sometimes reported as "edible" (with caution), you should absolutely not experiment. There may be several species in the aspera/acutesquamosa group (see the comments below) and we are in an era when Lepiota experts are discovering that traditional species lines in the genus are often inaccurate. Since several deadly, amatoxin-containing species look virtually identical (here is an example of a deadly contender), eating something that looks like this mushroom could be a fatal mistake. Description: Ecology: Saprobic; growing alone or scattered, usually in hardwood leaf litter or near woody debris; occasionally growing from well rotted wood; late summer and fall; possibly widely distributed, but more common in eastern North America. Cap: 3-11 cm; convex, becoming broadly convex or nearly flat in age; dry; when young densely covered with soft fibers that separate and become aggregated into small, sharp scales with maturity; orangish brown overall when young; when mature with orangish brown to dark brown scales over a whitish ground color that is exposed near the margin or nearly to the darker center. Gills: Free from the stem; white; close or crowded. Stem: 6-11 cm long; up to about 1.5 cm thick; more or less equal; dry; finely to densely hairy; with a ragged, flimsy but fairly persistent ring that cannot be easily detached and often features brown scales (like those on the cap) on its underside. Flesh: White. Odor and Taste: Odor usually mild, but sometimes fragrant or pungent; taste not distinctive. Taste is not a character that will help you identify Lepiota aspera, and I do not recommend testing it. Spore Print: White. Chemical Reactions: KOH on cap surface negative. Microscopic Features: Spores 6.5-11 x 2-3.5 µ; smooth; strongly to weakly dextrinoid; long-elliptical to nearly fusoid. Cheilocystidia to about 30 x 15 µ; clavate, cylindric, or nearly round. Pleurocystidia absent. Pileipellis an interwoven layer of narrow hyphae 2.5-8 µ in diameter, with scattered erect chains of inflated cells (the squamules on the cap surface). Clamp connections present. REFERENCES: (Persoon, 1793) Quélet, 1886. (Fries, 1821; Saccardo, 1887; Phillips, 1981; Hansen & Knudsen, 1992; Vellinga, 2003. Lepiota acutesquamosa: Kauffman, 1918; Kauffman, 1924; H. V. Smith, 1954; Smith, Smith & Weber, 1979; Bon, 1981; Lincoff, 1992; Barron, 1999; Miller & Miller, 2006.) Herb. Kuo 08030401, 10040505, 10050502, 09200601, 09220602. European mycologists (see Hansen & Knudsen, 1992, or the Index Fungorum) have synonymized Lepiota acutesquamosa (sometimes spelled "Lepiota acutaesquamosa") and Lepiota friesii with Lepiota aspera on the basis of morphology. A recent study by Vellinga (2003) found the DNA of European specimens identified as Lepiota aspera, Lepiota hystrix, and Lepiota perplexa to be genetically distinct but fairly closely related--though the study was not focused on the question of individual species within the aspera complex, and North American specimens identified as Lepiota acutesquamosa were not included. Until further research is done on this group of species, morphology-based identifications should probably be viewed as tentative. Further Online Information: Lepiota aspera at Roger's Mushrooms |
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Cite this page as: Kuo, M. (2007, October). Lepiota acutesquamosa. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/lepiota_acutesquamosa.html |