Astraeus hygrometricus (Pers.) Morgan
Family: Diplocystaceae
Hygroscopic Earthstar
Astraeus hygrometricus image
National Mushroom Centre  
Mata, M., D. Penjor and S. Pradham. 2010. Fungi of Bhutan. National Mushroom Centre, Ministry of Agriculture and Forests, Thimphu, Bhutan.

Local name: No local name known

Edibility: Inedible

Habitat: On dry sandy soil or under conifer trees and other different woods, scattered to gregarious.

Description: Fruiting bodies: 2-5 cm in diameter when young, globose which open to take star like forms, 5-8 cm in diameter and forming 4-20 rays of 2-4 cm long, surface dirty white or grey to brown. Outer surface: Exoperidium is beige brown, dry and cracks easily. Inner surface:  Endoperidium, gleba that is exposed after the fruit body opens, is 2-3 cm in diameter, is dirty white to brownish and has a hole in the apical part where the spores are released. Spore Print: Brownish. 

Comments: A. hygrometricus is easily recognized in the field by its hygroscopic rays. They open and close in response to humidity levels in environment; open when the humidity is high and closed when the humidity is low. This feature is very important for the mushroom because it can disperse the spores when the humidity is optimal and this ensures the conservation of the species.