Figure 19.—Agaricus silvicola. White to cream color, or yellow stains. (Natural size.) Copyright.
Agaricus (Psalliota) arvensis Schaeff. Edible.—The field mushroom, or horse mushroom, Agaricus arvensis, grows in fields or pastures, sometimes under trees and in borders of woods. One form is often white, or yellowish white, and often shows the yellow color when dried. The plant sometimes occurs in the form of a fairy ring as shown in Fig. [18]. It is 5–12 cm. high, the cap from 5–15 cm. broad and the stem 8–15 mm. in thickness.
The pileus is smooth, quite thick and firm, convex to expanded. The gills are first white, then tinged with pink and finally blackish brown. The stem is stout, nearly cylindrical, hollow, bulbous. The veil is double like that of Agaricus placomyces, the upper or inner layer remaining as a membrane, while the lower or outer layer is split radially and remains in large patches on the lower surface of the upper membrane.
Figure 20.—Agaricus silvicola, showing radiately torn lower part of veil. (Natural size.) Copyright.
Agaricus (Psalliota) silvicola Vittad. Edible.—The Agaricus silvicola grows in woods, groves, etc., on the ground, and has been found also in a newly made garden in the vicinity of trees near the woods. It is an attractive plant because of its graceful habit and the delicate shades of yellow and white. It ranges from 10–20 cm. high, the cap is 5–12 cm. broad and the stem 6–10 mm. in thickness.
The pileus becomes convex, and expanded or nearly flat, and often with an elevation or umbo in the center. It is thin, smooth, whitish and often tinged more or less deeply with yellow (sulfur or ochraceous) and is sometimes tinged with pink in the center. The flesh is whitish or tinged with pink. The gills when very young are whitish, then pink, and finally dark brown or blackish brown, much crowded, and distant from the stem. The stem is long, nearly cylindrical, whitish, abruptly enlarged below into a bulb. It is often yellowish below, and especially in drying becomes stained with yellow. The ring is thin, membranaceous, delicate, sometimes with broad, soft, floccose patches on the under side. The ring usually appears single, but sometimes the veil is seen to be double, and the outer or lower portion tends to split radially as in A. arvensis or A. placomyces. This is well shown in large specimens, and especially as the veil is stretched over the gills as shown in Fig. [20].