What You Should Know
Urnula craterium is a summer mushroom that first occurs from late May in southern Illinois until early autumn statewide. These rubbery look-alikes are not the famed Black Trumpet, and they’re not worth eating.
Fortunately, the Devil’s Urn won’t be a temptation for summer Black Trumpet hunters because this species occurs only during spring.
This mushroom growing singly or in small clusters, on sticks and small logs — though the wood is often buried, so they appear terrestrial.
Urnula craterium can be somewhat variable in appearance, and the relatively tough fruiting bodies can last for many weeks, given the right conditions. The overall shape is urn-like when the mushrooms are young, but the "mouth" of the urn gets wider as the mushrooms mature, and older specimens are often shaped more like goblets or cups.
Other names: Devil's Urn.
Urnula craterium Mushroom Identification
Saprobic on sticks and small logs (often buried) of hardwoods; growing alone, scattered, or in dense clusters; spring; widely distributed east of the Rocky Mountains.
5–9 cm high; 3–9 cm across; at first shaped like a deep cup or an urn with a vaguely defined stem portion; often expanding to goblet-shaped or cup-shaped with age.
Fertile (upper, or inner) surface
Dark brown to gray or nearly black; smooth and bald.
Sterile (lower, or outer) surface
Brown to gray or nearly black; bald, roughened, or scaly; often becoming finely cracked with age—or with pigments breaking up to form chevron-like or nearly reticulate patterns; the margin becoming lacerated and tattered.
Poorly defined at apex; 3–6 cm high; 0.5–1.5 cm wide; tapering to base; black; fuzzy toward the base.
White; tough; unchanging when sliced.
Hairy rubber cup (Galiella rufa) fruits July-September (not in spring), and its inner surface is a lighter, chocolate brown. Before the devil’s urn has opened, it may look like a dead man’s fingers (Xylaria polymorpha).
Urnula craterium Edibility
This species is often listed in field guides as inedible, or not recommended for consumption due to its tough texture. Michael Kuo, in his 2007 book on edible mushrooms, lists the taste as "mediocre", and comments "the devil's urn is not as bad as I thought it was going to be. It's not good, mind you, but it would be possible to eat it with a forced smile if your Aunt Wanda served it to you."
Urnula craterium Taxonomy
Urnula craterium was first described in 1822 by American botanist Lewis David de Schweinitz as Peziza craterium, based on a specimen found in North Carolina. The species first appeared in the scientific literature under its current name when Elias Magnus Fries described the new genus Urnula in 1849, and set Peziza craterium as the type species.
In 1896, German mycologist Heinrich Rehm removed the species from Urnula – transferring it to the genus Geopyxis – and replaced the type species with Urnula terrestris, a peripherally related species. This restructuring resulted in a taxomically untenable situation in which the genus Urnula consisted of a single species with ambiguous resemblance to the original species (described by Fries) upon which the genus was based.
Urnula craterium was placed with its related species under Geopyxis, because Geopyxis was established by Persoon before Urnula by Fries; and that to retain the genus Urnula, under which Saccardo had placed Podophacidium terrestre of Niessl, he (Rehm) restricted the genus to this latter fungus.
As Kupfer explains, Rehm did not justify why he believed Urnula craterium should be allied to Geopyxis, or why Podophacidium terrestre should be considered an Urnula. Kupfer's macro- and microscopic analysis of tissues from these and related genera clearly showed the inconsistency in Rehm's taxonomical choices, and that Urnula craterium represented an entirely different genus not related to Geopyxis; Fries's naming was restored.
The genus name means "little urn"; the specific epithet is derived from the Latin cratera, referring to a type of bowl used in antiquity to mix wine with water. It is commonly known as the devil's urn and the gray urn.
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