A small, cushion-shaped puffball of dry, open, sparsely vegetated ground. It is one of the Disciseda species that start out upside down; its outer crust of soil or sand grains bound by hyphae wears away to a small basal patch, and spores escape through an apical mouth. The species concept probably hides several cryptic species.
Dry, exposed habitats with bare soil and only low mosses and herbs: dry grassland, sand dunes, steppe and dry Arctic vegetation; favors moderate disturbance such as trampling, and also grows on farmyards and field tracks.
Distribution
Described from North America and reported from Eurasia, North and South America, Greenland, Australia and New Zealand; abundant in Europe. Molecular data suggest a complex of cryptic species, so many records are ambiguous. It is Red Listed in Norway (Endangered), Denmark (Critically Endangered) and Sweden (Vulnerable), mainly at the edges of its range, where loss of grazing lets tall grass overgrow its sites.
Characteristics
Fruit body: a flattened, cushion-like spore sac up to about 3 cm across and about half as tall as wide, opening by a small apical mouth. Exoperidium: a crust of soil or sand grains bound by hyphae, covering about half of the young fruit body and eroding to a small basal patch. Endoperidium: whitish, gray or brown; its lower part has a net-like pattern formed by tufts of hyphae, which a thick endoperidium can hide and which NatureMapr says sets it apart from its look-alikes. Some American and Australian specimens have a translucent gelatinous layer between the two skins; European specimens reportedly lack it.
