Order 2. Sphærobolaceæ. An intermediate layer of the peridium swells when ripe, becomes convex, and ejects the remaining spherical portion of the fruit-body which contains the spores. Sphærobolus carpobolus has small, spherical fruit-bodies which open in the form of a star.
Fig. 179.—Phallus impudicus (Stink-horn), somewhat diminished. Fruit-bodies in all stages of development (b, c, d and k-m) are seen arising from a root-like mycelium (a); d longitudinal sections through a fruit-body before the covering has ruptured.
Family 4. Gasteromycetes.
The fruit-body is angiocarpic, fleshy at first, and later generally more or less hard and continues closed after the spores are ripe. The tissue lying immediately inside the peridium is termed the gleba; it is porous, containing a larger or smaller number of chambers lined with the hymenium, which is either a continuous layer of basidia or else it fills up the entire cavity. The basidia as a rule bear four spores, sometimes eight (Geaster), or two (Hymenogaster). The tissue of the walls (trama) consists often (Lycoperdaceæ) of two kinds of hyphæ, some thin and rich in protoplasm, divided by transverse septa and bearing the basidia; others thicker and thick-walled which do not dissolve like the former on the ripening of the spores, but continue to grow and form a woolly, elastic mass, the capillitium, which may be regarded as highly developed paraphyses. The peridium may be either single or double, and presents many variations in its structure and dehiscence. The mycelium is generally a number of string-like strands, living in soils rich in humus.
Order 1. Tylostomaceæ. Capillitium present. After the rupture of the peridium the remaining part of the fruit-body is elevated on a long stalk. Tylostoma mammosum, on heaths.
Order 2. Lycoperdaceæ. The fruit-body has a double peridium; the external one at length breaks into fragments (Lycoperdon, Bovista), or it has a compound structure of several layers (Geaster) and detaches itself as a continuous envelope from the inner layer, which is membranous and opens at its apex. The interior of the fruit-body consists either solely of the fertile gleba (Bovista, Geaster), or, in addition, of a sterile tissue at the base (Lycoperdon). A capillitium is also present.
Fig. 180.—Lycoperdon gemmatum (½ nat. size).
Lycoperdon (Puff-ball) has a sterile part at the base of the fruit-body which often forms a thick stalk. The surface of the peridium is generally covered with warts or projections. When young this Fungus is edible, but when ripe it is dry, and used for stopping the flow of blood. L. giganteum, which is often found growing in meadows, attains a considerable size, its diameter reaching as much as eighteen inches. L. gemmatum (Fig. [180]) is covered with pyramidal warts; in woods.—Bovista has no sterile basal part; the external peridium is smooth, and falls away in irregular patches. B. plumbea, on links near the sea.—Geaster (Earth-star) has an external peridium composed of several layers, which when the fruit-body opens, split into several stellate segments. These segments are very hygroscopic, and in dry weather bend backwards and so raise the inner peridium into the air. The inner peridium contains the spores and capillitia. G. coliformis has several apertures in the inner peridium. The other species have only one regular aperture at the apex. G. striatus has a pedicellate inner peridium, with conical, striped peristome. G. fornicatus has an external peridium split into four segments. This last and several other species produce “mycorhiza” on the roots of Conifers.