1. The purple-brown-spored agarics.
  2. The black-spored agarics.
  3. The white-spored agarics.
  4. The rosy-spored agarics.
  5. The ochre-spored agarics.

FOOTNOTES:

[A] For analytical keys to the families and genera see Chapter [XXIV].

CHAPTER IV.

THE PURPLE-BROWN-SPORED AGARICS.[B]

The members of this subdivision are recognized at maturity by the purple-brown, dark brown or nearly black spores when seen in mass. As they ripen on the surface of the gills the large number give the characteristic color to the lamellæ. Even on the gills the purple tinge of the brown spores can often be seen. The color is more satisfactorily obtained when the spores are caught in mass by placing the cap, gills downward, on white paper.

AGARICUS Linn. (PSALLIOTA Fr.)

In the genus Agaricus the spores at maturity are either purple-brown in mass or blackish with a purple tinge. The annulus is present on the stem, though disappearing soon in some species, and the stem is easily separated from the substance of the pileus. The gills are free from the stem, or only slightly adnexed. The genus is closely related to Stropharia and the species of the two genera are by some united under one genus (Psalliota, Hennings). Peck, 36th Report, N. Y. State Mus., p. 41–49, describes 7 species. Lloyd Mycol. Notes, No. 4, describes 8 species. C. O. Smith, Rhodora, I: 161–164, 1899, describes 8 species.

Agaricus (Psalliota) campestris Linn. Edible.—This plant has been quite fully described in the treatment of the parts of the mushroom, and a recapitulation will be sufficient here. It grows in lawns, pastures, by roadsides, and even in gardens and cultivated fields. A few specimens begin to appear in July, it is more plentiful in August, and abundantly so in September and October. It is 5–8 cm. high (2–3 inches), the cap is 5–12 cm. broad, and the stem 8–12 mm. in thickness.

The pileus is first rounded, then convex and more or less expanded. The surface at first is nearly smooth, presenting a soft, silky appearance from numerous loose fibrils. The surface is sometimes more or less torn into triangular scales, especially as the plants become old. The color is usually white, but varies more or less to light brown, especially in the scaly forms, where the scales may be quite prominent and dark brown in color. Sometimes the color is brownish before the scales appear. The flesh is white. The gills in the young button stage are white. They soon become pink in color and after the cap is expanded they quickly become purple brown, dark brown, and nearly black from the large number of spores on their surfaces. The gills are free from the stem and rounded behind (near the stem). The stem is white, nearly cylindrical, or it tapers a little toward the lower end. The flesh is solid, though the central core is less firm. The veil is thin, white, silky, and very frail. It is stretched as the cap expands and finally torn so that it clings either as an annulus around the stem, or fragments cling around the margin of the cap. Since the annulus is so frail it shrivels as the plant ages and becomes quite inconspicuous or disappears entirely (see Figs. 1–7).