Wikipedia:Today's featured article/October 24, 2017
Astraeus hygrometricus, the false earthstar, is a fungus common in temperate and tropical regions around the world. When young, it resembles a puffball; in maturity, the outer layer of fruit body tissue splits open in a star shape, similar in appearance to the earthstars. The fungus grows in mutual symbiosis with roots of various trees, especially in sandy soils. It can open up its rays to expose the spore sac in response to increased humidity, and close them up again in drier conditions. The rays have an irregularly cracked surface, while the spore case is pale brown and smooth with an irregular slit or tear at the top. The gleba is white initially, but turns brown and powdery when the reddish-brown spores mature. The species was first described by Christiaan Hendrik Persoon in 1801. Several bioactive chemical compounds have been found in the fruit bodies. North American field guides typically rate the fungus as inedible. (Full article...)