PDD 74967, 74969, 74970.

Fruiting body a stalked or (occasionally) sessile sporangium, scattered to gregarious, 1–2.5 mm tall. Sporotheca pulvinate or globose to elliptic or obovate, 0.6–1.2 mm in diameter. Stalk usually present, black, rather short, stout, but sometimes equalling or exceeding the sporotheca in height. Hypothallus discoid, membranous. Peridium dark purple black with a silvery sheen, fragile, fugacious, breaking up above into small fragments that tend to adhere to the capillitium, usually thicker and persistent at the base. Columella cylindrical or clavate, often stout, reaching nearly to the center of the sporotheca. Capillitium olive-brown to black, the tips expanded, particularly below, into funnel-shaped yellowish-brown enlargements that are attached to the peridium, fragments of which may persist as conspicuous, irregular disks or plates. Spores black in mass, dark by transmitted light, coarsely echinate, the short, blunt spines sometimes arranged in sinuous lines over a portion of the surface, forming an indistinct and incomplete reticulation, 12–15 µm in diameter. Plasmodium black.

Widely distributed in the mountains of western North America and Europe (Martin & Alexopoulos 1969, Kowalski 1970), where it is associated with melting snowbanks in late spring and early summer. First reported from New Zealand by Stagg (1982), based on a specimen collected in Westland. Also known from Marlborough, Central Otago, and Mackenzie.

Living plants and plant debris at the edges of snowbanks in alpine regions.

Martin & Alexopoulos (1969), Ing (1999), Neubert et al. (2000).

The peridium in Lamproderma atrosporum is usually fugacious, but minute fragments remain attached to the expanded tips the capillitium (especially below), and this feature alone makes this species relatively easy to identify.