Helvella acetabulum is a species of fungus in the family Helvellaceae, order Pezizales. This relatively large cup-shaped fungus is characterized by a tan fruit body with prominent branching ribs resembling a cabbage leaf; for this reason it is commonly known as the cabbage leaf Helvella. Other colloquial names include the vinegar cup and the brown ribbed elfin cup. The fruit bodies reaches dimensions of by tall. It is found in Asia, Europe, and North America, where it grows in sandy soils, under both coniferous and deciduous trees. Taxonomy The fungus was first named as Peziza acetabulum by Carl Linnaeus in his 1753 Species Plantarum. It was given its current name by French mycologist Lucien Quélet in 1874 after having been placed in various Peziza segregates: Joachim Christian Timm placed it in Octospora (1788), Samuel Frederick Gray in Macroscyphus (1821), and Leopold Fuckel in Acetabula (1870). The trend continued, with Claude Casimir Gillet with placing it in Aleuria in 1879, and Otto Kuntze in his new Paxina (of which it would later be designated type species) in 1891. Described independently as Peziza sulcata by Persoon in 1801, it was placed under that name in both Paxina and Acetabula—alongside its precursor as both taxa were still considered separate at the time. Finally, Frederic Clements renamed Acetabula as Phleboscyphus in 1903 and improperly reused Fuckel's name as the basionym of his Phleboscyphus vulgaris. The specific epithet acetabulum means "little vinegar cup", and was the Latin word for a small vessel used for storing vinegar (see acetabulum). Common names include the "cabbage leaf Helvella", the "vinegar cup", the "ribbed-stalk cup", and the "brown ribbed elfin cup". Description Helvella acetabulum has a deeply cup-shaped fruit body (technically an apothecium) that is up to in diameter, and deep. The inner spore-bearing surface, the hymenium, is brown, and may be smooth or slightly wavy; the exterior surface is cream-colored, and is covered with minute "hairs". The ribs start from the cream-colored stem and extend almost to the edge of the fruit body. The stem is typically tall by thick. The odor and taste of this mushroom are not distinctive. The spores are smooth, elliptical, translucent (hyaline), and contain a single central oil droplet; they have dimensions of 18–20 by 12–14 µm. The spore-bearing cells, the asci, are 350–400 by 15–20 µm, are operculate—meaning they have an apical "lid" that releases the spores. The tips of the asci