Helvella acetabulum
Anamorph: not known.
Teleomorph: ascomata apothecia, 1.5-7 cm broad, at first regularly cupulate, when adult expanded and irregular, hymenium brownish to dark brown, sometimes with a violet tinge, outside pubescent, above greyish brown to brown, below gradually becoming pale brownish to nearly whitish-cream, with prominent whitish to cream, angular to sharp-edged branching ribs, which may reach the margin; stipe mostly well-developed, inside chambered, 2-6 cm high, not clearly distinct from the gradually widening apothecium. Paraphyses 4-6 µm diam., slightly enlarged above, walls ± brownish. Asci 16-21 µm broad, cylindrical, the apex rounded, 8-spored. Ascospores 16-18 (-19) x 11-12 µm, broadly ellipsoidal.
Description mostly adapted from Dissing (1966).
Distinguished by the pale to mid brown irregularly cupulate apothecia, rather short-stalked and with the stalk furrowed and merging with the outer exciple of the apothecium.
On soil beneath broadleaved trees, especially Fagus and Quercus.
Quite common, more or less throughout Britain.