Astraeus hygrometricus (Pers.) Morg. syn. Geastrum hygrometricum Pers. Wetterstern, Géastre en étoile, Barometer Earthstar Fruit body 1–5cm across, globose, outer wall ochraceous tan to dark brown, splitting into 6–15 pointed rays on maturity when moist, closing and becoming hard and leather-like when dry. Spore sac 1–3cm across, pallid to dark greyish, thin and papery opening by a slit or tear forming an irregular pore. Gleba cocoa-brown at maturity. Spores cinnamon-brown, globose and finely warted, 7–10.5µ in diameter. Habitat dunes or sandy soil in woods, developing just below the surface and becoming exposed at maturity. Season autumn but persisting in good condition for up to a year. Rare. Not edible. Distribution, America and Europe.