| astreus | (n) a genus of fungi belonging to the family Geastraceae, Syn. genus Astreus |
| astreus hygrometricus | (n) a common species of earthstar widely distributed in sandy soil; the gleba is a pale tan |
| astreus pteridis | (n) the largest earthstar; the fruiting body can measure 15 cm across when the rays are expanded |