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Gyromitra leucoxantha

[ Ascomycetes > Pezizales > Discinaceae > Gyromitra . . . ]

by Michael Kuo

Despite appearances, this cup fungus is actually closely related to the false morels, and officially belongs in the genus Gyromitra. To the naked eye it is more or less indistinguishable from a host of other brownish, springtime cup fungi (including Disciotis venosa, Peziza arvernensis, and others). Under the microscope, however, it is clearly distinct from most look-likes.

Field guides, which usually treat this species as "Discina leucoxantha," emphasize yellowish colors and a fairly well developed (but small) stem structure for Gyromitra leucoxantha, but I would not bet the house on any cup-like Gyromitra identification without examining spores. Mature Gyromitra leucoxantha spores have distinctive, blunt (rather than pointy) and "scooped-out" extensions at either end.


Ecology: Saprobic; growing alone or gregariously; terrestrial, but like many species of Gyromitra often appearing near rotted wood and stumps; found under hardwoods and conifers, in spring; northern, northeastern, and montane North America.

Fruiting Body: 4-10 cm across; cup-shaped or bowl-shaped when young; flattening out with maturity, becoming irregularly saucer-shaped. Upper surface yellow to yellowish brown or orangish brown; smooth at first but usually becoming wrinkled or bumpy, at least over the center. Undersurface whitish and very finely hairy (use a lens); sometimes bruising brownish. Stem (usually present) to 5 cm long and 3 cm wide; whitish; continuous with undersurface. Flesh 2-3 mm thick; watery whitish.

Microscopic Features: Mature spores 28-40 x 12-16 µ; with one or two oil droplets; smooth or roughened; with blunt, "scooped-out" apiculi at each end, extending up to 4 µ (best seen in a water mount). Asci 8-spored. Paraphyses cylindric to clavate; to 8 µ wide; with orangish to yellowish granular contents in a KOH mount.

REFERENCES: (Bresàdola, 1881) Harmaja, 1969. (Saccardo, 1889; McKnight, 1969; Smith, Smith & Weber, 1981; Breitenbach & Kränzlin, 1984; Weber, 1995; Abbott & Currah, 1997.) Herb. Kuo 05259504, 05299506, 06029602, 05230503, 05090606.

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Gyromitra leucoxantha

Gyromitra leucoxantha

Gyromitra leucoxantha

Gyromitra leucoxantha

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Kuo, M. (2012, June). Gyromitra leucoxantha. Retrieved from the MushroomExpert.Com Web site: