noun
barometer earthstar
A species of fungus (Astraeus hygrometricus) known for its hygroscopic rays that open and close with humidity. The name is usually written in katakana as ツチグリ.
ツチグリは雨の後に地面に現れることがある。
Barometer earthstars sometimes appear on the ground after rain.
このキノコはツチグリと呼ばれ、湿度で形が変わる。
This mushroom is called tsuchiguri, and its shape changes with humidity.
The name ツチグリ (土栗) literally means 'earth chestnut', likely from its round, chestnut-like appearance when closed. The exact origin is uncertain.