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Amanita jacksonii

[ Basidiomycetes > Agaricales > Amanitaceae > Amanita . . . ]

by Michael Kuo

The North American versions of the European species Amanita caesarea are numerous and confusing, and their taxonomy has not yet been completely established. The principal (mushroom) players in this drama are fairly easily recognized by their yellow gills, their large, white, sacklike volvas, and their bright orange or orange red caps, which have lined margins. Heading up the cast (for the taxonomical moment, anyway) is Amanita jacksonii. It is an impressive eastern actor, appearing in woodland theaters from the province of Québec to the state of Hidalgo, and recognized by its brilliant colors, the slender yellow stem with reddish to orange fibers, the fact that the cap begins to fade to yellow from the margin inward, and microscopic features.


Ecology: Mycorrhizal with oaks and pines; summer and fall; widely distributed east of the Great Plains, from Québec to Hidalgo.

Cap: 5-12 cm; oval at first, becoming convex, typically with a central bump; sticky when fresh; brilliant red or orange, fading to orange, or yellow on the margin; bald; typically without warts or patches; the margin lined for about 40-50% of the cap's radius.

Gills: Free from the stem or slightly attached to it; yellow to orange-yellow; close or crowded; short-gills frequent.

Stem: 9-15 cm long; 1-1.5 cm thick; slightly tapering to apex; yellow; with orange to reddish fibers, often in zones; not bruising; with a yellow to orange, skirtlike ring; with a large (4-7 cm high and 4 mm thick), white, sacklike volva.

Flesh: Whitish to pale yellow; not staining on exposure.

Odor: Not distinctive.

Chemical Reactions: KOH on cap surface erasing pigment to yellow.

Spore Print: White.

Microscopic Features: Spores 8-11 x 5-6.5 µ; ellipsoid; smooth; inamyloid. Basidia 4-spored; clamped. Pileipellis a cutis of gelatinizing hyphae 2-7 µ wide. Lamellar trama bilateral; subhymenium cellular.

REFERENCES: Pomerleau, 1984. (Jenkins, 1986; Roody, 2003; McNeil, 2006; Binion et al., 2008; Kuo & Methven, 2010; Tulloss, 2013.) Herb. Kuo 10200704, 09200806.

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Amanita jacksonii

Amanita jacksonii

Amanita jacksonii

Amanita jacksonii

Amanita jacksonii

Amanita jacksonii

Amanita jacksonii

Cite this page as:

Kuo, M. (2013, May). Amanita jacksonii. Retrieved from the MushroomExpert.Com Web site:

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