Lactarius indigo (Schw.) Fr.—The indigo blue lactarius is a very striking and easily recognized plant because of the rich indigo blue color so predominant in the entire plant. It is not very abundant, but is widely distributed in North America. The plant is 5–7 cm. high, the cap 5–12 cm. broad, and the stem is 1–2 cm. in thickness. The plants occur during late summer and in the autumn.

The pileus when young is umbilicate, the margin involute, and in age the margin becomes elevated and then the pileus is more or less funnel-shaped. The indigo blue color is deeply seated, and the surface of the pileus has a silvery gray appearance through which the indigo blue color is seen. The surface is marked by concentric zones of a darker shade. In age the color is apt to be less uniformly distributed, it is paler, and the zones are fainter. The gills are crowded, and when bruised, or in age, the indigo blue color changes somewhat to greenish. The milk is dark blue.

RUSSULA Pers.

The species of Russula are very characteristic, and the genus is easily recognized in most cases after a little experience. In the very brittle texture of the plants the genus resembles Lactarius, and many of them are more brittle than the species of this genus. A section of the pileus shows under the microscope a similar vesicular condition, that is the grouping of large rounded cells together, with threads between. But the species of Russula are at once separated from those of Lactarius by the absence of a juice which exudes in drops from bruised parts of Lactarius. While some of the species are white and others have dull or sombre colors, many of the species of Russula have bright, or even brilliant colors, as red, purple, violet, pink, blue, yellow, green. In determining many of the species, however, it is necessary to know the taste, whether mild, bitter, acrid, etc., and in this respect the genus again resembles Lactarius. The color of the gills as well as the color of the spores in mass should also be determined. The genus is quite a large one, and the American species are not well known, the genus being a difficult one. In Jour. Mycolog., 5: 58–64, 1889, the characters of the tribes of Russula with descriptions of 25 species are quoted from Stevenson, with notes on their distribution in N. A. by MacAdam.

Russula alutacea Fr. Edible.—This handsome Russula differs from the others described here in the color of the gills and spores. The plant is common and occurs in mixed woods during the summer and early autumn. It is 5–10 cm. high, the cap 5–12 cm. broad, and the stem 1.5–2.5 cm. in thickness.

The pileus is fleshy, oval to bell-shaped, becoming plane, and sometimes umbilicate. It is red or blood red in color, sometimes purple, and becoming pale in age, especially at the center. It is viscid when moist, the margin thin and striate-tuberculate. The gills are free from the stem, stout, broad, first white, becoming yellow, and in age ochraceous. The gills are all of the same length, not crowded, and they are connected by vein-like elevations over the surface. The stem is stout, solid, even, white, portions of the stem are red, sometimes purple.

The taste is mild, and the plant is regarded as one of the very good ones for food.

Russula lepida Fr. Edible.—This elegant Russula occurs in birch woods or in mixed woods during late summer and autumn. It is 5–8 cm. high, the cap 6–8 cm. broad, and the stem 1–2 cm. in thickness.