Auricularia americana

Auricularia americana forms thin, brown, rubbery-gelatinous fruit bodies that are ear-shaped and 2.5–10 centimetres (1–4 inches) across and about 3 millimetres (1⁄8 in) thick.^[3] The fruitbodies occur singly or in clusters. The upper surface is finely pilose. The spore-bearing underside is smooth.^[2] The spore print is white.^[3]

The microscopic characters are typical of the genus Auricularia. The basidia are tubular, laterally septate, 55–70 × 4–5 μm. The spores are allantoid (sausage-shaped), 14–16.5 × 4.5–5.5 μm.^[2]

In North America, Auricularia angiospermarum is almost identical but grows on the wood of broadleaf trees. No other North American Auricularia species grows on conifer wood. In China and Tibet, however, a second species, A. tibetica, also occurs on conifers. It can be distinguished microscopically by its longer basidia and larger basidiospores.^[1][2]

Additionally, A. nigricans, Exidia crenata, and Phylloscypha phyllogena are similar.^[3]

Auricularia americana is a wood-rotting species, typically found on dead attached or fallen wood of conifers. It is widely distributed in North America (primarily in the Northeast, between April and September)^[3] and is also known from China and the Russian Far East.^[2]