G. hygrome´tricus Pers. (Plate [CLX], 2 figs., p. 580.) Peridium depressed-globose, the cuticle deciduous with the mycelium; outer peridium deeply parted, the segments 7–20, strongly hygrometric, acute at the apex; inner peridium depressed-globose, sessile, reticulate, pitted, whitish becoming gray or brownish; the mouth an irregularly lacerate aperture. Threads of the capillitium rather thinner than the spores, hyaline. Spores globose, minutely warted, brown, 8–11µ in. in diameter.
Growing in fields and woods in sandy soil. A very common species found everywhere in the world. Inner peridium ¾-1 in. in diameter, the segments expanding to a breadth of 2–3 in. The inner layer of the outer peridium is cartilaginous-gelatinous, hard and rigid when dry, swelling greatly and flexible when wet though constantly becoming more and more cracked and fissured, it retains its hygroscopic qualities a long time, and the outer peridium remains lying on the soil, stellate in shape, spreading out its rays in moist weather and bending them inward in dry. Morgan.
Mr. Morgan made a new genus—Astræus, in which he placed this species. It is so widely known as Geaster hygrometricus that to avoid confusion it is placed in its old genus.
This natural barometer, spreading its stellate covering on the soil about it when the air is laden with moisture, and closing it around its puffy body when humidity is absent, is odd and interesting. The entire genus is more or less gifted with this weather-wise quality. The species is very common, but seldom found in number. Once, in the West Virginia mountains, 1882, I found a large patch of it, and was able to collect from it enough young ones to test its edibility. It is difficult to find before it bursts its outer coat. When young it is, when cooked, soft and creamy inside. The outer part is tough and semi-glutinous but of pleasant texture. It has not a marked flavor, but makes a succulent dish.
II.—CORTICATÆ.
GENUS VII.—TYLOS´TOMA Pers.
Gr—a knob.
