Brown-haired White Cup

Humaria hemisphaerica has fruiting bodies (apothecia) that typically measure 5 to 30 millimetres (1⁄4 to 1+1⁄8 inches) in diameter by 1 to 1.5 cm (3⁄8 to 5⁄8 in) deep. The fruiting bodies are initially spherical and expand to become cuplike at the fungus matures. This species typically does not have a stipe; when it does, it is present as a small abrupt base. The inner surface of the fruiting body (the hymenium) is white, while the outer hairy surface is brown and covered with brown hairs that taper to a sharp point. These hairs are 400–500 x 15–20 μm. The ascospores are elliptical, hyaline, 20–22 x 10–11 μm, and have 2–3 oil droplets.

Similar species. Similar species of Humaria may exist in North America, but are not circumscribed. There are several other similar cup fungi in the Pyronemataceae family with hairy exteriors. Jafnea semitotsa is larger (2–5 cm in diameter) with a brown interior and a short stipe. The cups of Trichophaea species are usually less than 1 cm across; Trichophaea boudieri and T. bullata are 1–6 millimetres wide, and T. abundans prefers to grow in burnt areas. Chaetothiersia vernalis grows in a more disclike form, and Wilcoxina rehmii produces tiny discs.

H. hemisphaerica grows year-round on North America's west coast and is common in the Pacific Northwest; further east, it fruits from July to October. Specimens usually grow alone, but also appear scattered or grouped on the ground, and sometimes on decaying wood.