The Geasters or Earth-stars are the most picturesque forms of the puffballs. At first they are sunk deep in the soil, and are connected with it by abundant thread-like mycelium, which issues from every part of the surface. In the earth-stars the covering to the pouch is double, the outer cover is thick and leathery, and at first closely invests the inner coat, but is separate from it. At maturity the outer coat breaks its connection with the mycelium in the soil and bursts to form separate lobes, which become reflexed and lift the inner ball from the ground into the air, where it remains, seated at the centre of the expanded starlike coat. The coat of this ball is thin and papery, and opens by one apical mouth. The threads or capillitium, which bear the spores, project from the tissue of the inner wall and also from a central columella.
The Geasters have no economic value, but are rather interesting to the nature student on account of their beauty and their curious methods of discharging their spores.
The Smallest Earth-star
Peridium or Pouch - Globose, depressed, not pointed; vaulted underneath. Bark or Outer Coat - Segments acute at the apex, many lobed; the lobes, seven to nine, expanding 1/2-1 inch. Inner Coat - Ovoid, 1/4-1 inch in diameter, white to pale brown, with a distinct pedicel, seated in a plain circular disk. Mouth - Lifted on a cone, lip bordered with hair-like fringe. Spores - Brown, globe-shaped, minutely warted. Threads - Transparent. Habitat - Grassy grounds.
Water-measuring Earth-star Geaster 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 breadth of 2-5 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 Astrams hygrometricus as it is called by some, is found all over the world. When the Genus Calostoma 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.
Calostoma Ravenelii (Berk.) Mass.
Calostoma lutescens (Schw), Burnap.
Calostoma cinnabarinum, Desv.
Spathularia velutipes, C. & F. Reduced. See page 138.