About this fungus
Hygroscopic Earthstar is a fungus in the Diplocystidiaceae family. Its habitat and field characteristics are summarised below.
A southern European false earthstar whose tough rays open in damp conditions and curl back over the central spore sac as they dry.
What to check
Confirm thick leathery hygroscopic rays with a cracked inner surface and a central spore sac that opens irregularly rather than through the neat, structured pore typical of many Geastrum. Mature shape supports the genus, but microscopy and geographic evidence are needed for the strict species.
Lookalikes
Astraeus was long treated as one worldwide species, but North American and Asian collections now belong to other regional taxa, including Astraeus pteridis, Astraeus morganii and Astraeus smithii in North America. Geastrum earthstars usually have thinner rays and a more regular pore.
Habitat and range
Ectomycorrhizal on dry, sandy or free-draining soil with trees and shrubs. Current evidence restricts Astraeus hygrometricus in the strict sense to southern Europe rather than treating every hygroscopic false earthstar worldwide as this species.
Food safety
Inedible.