page_title: Urnula craterium
section_title: Description
hierarchical_section_title: Urnula craterium / Description
caption_attribution_description: English: A bisected specimen of Urnula craterium (Schweinitz) Fries, commonly known as the "Devil's Cup'". Photographed in Strouds Run State Park, Athens, Ohio, USA.
context_page_description: Urnula craterium is a species of cup fungus in the family Sarcosomataceae. It is parasitic on oak and various other hardwood species; it is also saprobic, as the fruit bodies develop on dead wood after it has fallen to the ground. Appearing in early spring, its distinctive goblet-shaped and dark-colored fruit bodies have earned it the common names devil's urn and the gray urn. The distribution of U. craterium includes eastern North America, Europe, and Asia. It produces bioactive compounds that can inhibit the growth of other fungi. The asexual, or conidial stage of U. craterium is a plant pathogen known as Conoplea globosa, which causes a canker disease of oak and several other hardwood tree species.
context_section_description: The fruit bodies begin from dense, black mycelium on the surface of oak branches in contact with the ground. Starting out as rolls of cylindrical tissue 1 or more centimeters long and 3–4 mm wide, they expand slowly over the winter, and grow rapidly in the spring when the weather becomes warmer.
  The goblet-shaped fruit body (technically an ascocarp) is 3–4 cm (1.2–1.6 in) in diameter and 4–6 cm (1.6–2.4 in) deep; initially it is closed, but opens as it matures, leaving a ragged or smooth inrolled margin around a round opening. The flesh of the ascocarp walls is tough and initially gelatinous, later becoming leathery. The exterior of the ascocarp is brownish black to black, with a velvety surface, while the interior spore-bearing surface, the hymenium, is brownish black in color, usually somewhat paler than the outside. The outer surface may be partially covered with small flakelike patches of tissue. When viewed with a magnifying glass, the "hairs" (fungal hyphae) making up the outer velvety surface are variable in length, and are thick-walled, blunt, and appear to wind from side to side (flexuous). The ascocarp is connected to a stalk that is typically 3–4 cm (1.2–1.6 in) long by 0.4–0.8 cm (0.2–0.3 in) thick, with black mycelia at its base.
caption: A bisected immature specimen with cup not yet opened
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