Geaster HygrometricusGeaster hygrometricus
Peridium or Pouch - Sub-globose, depressed, the bark or skin falling with the mycelium.
Bark or Outer Coat - Deeply parted; the segments, acute at the apex, seven to twenty. Strongly hygrometric, expanding to a breath of 2-3 inches.
Inner Coat - Globose, depressed, sessile, covered with a network. Whitish or greyish.
Mouth - Rim irregular.
Spores - Brown, globe-shaped, minutely warted.
Threads - Transparent, much branched and interwoven; continuous with the hyphae or threads of the inner coat.
Habitat - Fields and woods, in sandy soil.
The Geaster hygrometricus, or Astraeus hygrometricus as it is called by some, is found all over the world. When the weather is wet, the lining of the points of the star become gelatinous and lie flat on the ground, anchoring the plant firmly; but when the weather is dry, the soft, gelatinous part becomes hard and rigid, and curls the segments up around the inner ball; then the wind rolls it about, and it scatters its spores from the hole in the apex of the ball as it rolls. It is a fair-weather traveller, always resting at night and on damp days.