What You Should Know
Disciotis venosa is a species of fungus in the family Morchellaceae. Fruiting in April and May, they are often difficult to locate because of their nondescript brown color. Found in North America and Europe, they appear to favor banks and slopes and sheltered sites. Although D. venosa is considered edible, it may resemble several other species of brown cup fungi of unknown edibility.
This cup fungus is a close relative of the morels - though you would need a microscope to discover why. By maturity, the wrinkled and veined center of Disciotis venosa is often fairly distinctive, but various species of Peziza and Gyromitra (namely, the cup-like species formerly placed in Discina) can be dead-ringers to the naked eye.
Most other brown cup fungi are very smooth on the inside, but Disciotis venosa has raised vein-like ridges, as its name would suggest. These veins may serve to increase the surface area for bearing asci with their ascospores, but not by much.
Other names: Bleach Cup, Veiny Cup Fungus, Cup Morel, Veined Cup.
Disciotis venosa Mushroom Identification
Probably saprobic, but since it is closely related to the morels, possibly at least facultatively mycorrhizal; found primarily under hardwoods, in beech-maple and oak-hickory forests in eastern North America, and in riparian woods in the west; growing alone, scattered, or gregariously; spring (usually during morel season); widely distributed in North America.
4-21 cm across; shaped more or less like a cup when young, often with a curled-in edge; in age flattening and becoming irregularly saucer-shaped; upper surface yellowish-brown to brown or reddish-brown, bald; smooth at first but soon becoming wrinkled or veined, especially over the center; undersurface whitish to pale tan, often dotted with tiny brown scales, rough or finely hairy; pinched together in the center to form a very short pseudo-stem that is buried in the ground; flesh brittle and pale brownish.
Spores 22-25+ x 12-15 µ; smooth; elliptical; without oil droplets; contents homogeneous. Asci 8-spored; not bluing in Melzer's reagent or IKI. Paraphyses septate; apices clavate to subcapitate; to about 10 µ wide; with brownish contents.
Species that may resemble Disciotis venosa include the "thick cup", species Discina perlata (also edible), as well as several species of Peziza. Peziza species generally have thinner flesh than D. venosa, and will turn a dark blue color if a drop of iodine solution is placed on it. Additionally, the tips of asci in Peziza species will stain blue with iodine, a feature that can be observed with a light microscope. Another lookalike, Discina ancilis, has an inner cup surface that is folded, wrinkled, or sometimes smooth, rather than veined. The outer cup surface has small tufts of hairs arranged in clumps.
Disciotis venosa Taxonomy and Etymology
Bleach Cup was described scientifically in 1801 by Christiaan Hendrik Persoon, who gave it the scientific name Peziza venosa. In 1893 the great Swedish mycologist Elias Magnus Fries transferred this species to the genus Disciotis, establishing its currently-accepted scientific name Disciotis venosa.
Peziza venosa Pers. (1801)
Discina venosa (Pers.) Fr. (1822)
Discina venosa var. rabenhorstii Sacc. (1889)
Disciotis venosa f. radicans Perco (1994)
The generic name Disciotis reflects the disc-like form of mature specimens of these virtually stemless fungi, while the specific epithet venosa comes from Latin and refers to the vein-like wrinkled central region of mature fruitbodies.
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