Lactarius piperatus Scop. Peppery Lactarius. Cap fleshy, compact, convex and slightly umbilicate, at last deeply depressed, becoming funnel-formed, smooth and even; gills decurrent, very narrow, thin, even and close together, dichotonous, white; flesh white; milk white, extremely acrid, copious; stem very short, stout, solid. Whole plant white.
Lactarius blennius Fries. Cap depressed, slimy or glutinous, greenish-gray; margin incurved and somewhat downy. Gills narrow, white or whitish; stem stuffed or hollow, viscid, and of same color as the cap or paler; milk white and very acrid.
M. C. Cooke divides the genus Lactarius into 4 "Tribes": (1) Piperites, in which the stem is central, gills unchangeable, naked, neither discolored nor pruinose, milk at first white and commonly acrid; (2) Dapetes, in which the stem is central, gills naked, milk from the first deeply colored; (3) Russulares, in which the stem is central, gills pallid, then discolored, becoming darker, changing when turned to the light, at length pruinose, with milk at first white and mild and sometimes becoming acrid; (4) Pleuropos, in which the stem is concentric or lateral.
To the first of these subdivisions, Piperites, belong all of the Lactars enumerated above. The Russians eat the Piperites only after the water of the first boiling has been taken off.
Lactarius rufus Scop., a very acrid species of large size, having reddish ochraceous gills and zoneless cap of reddish yellow with white milk, belongs to the subdivision Russulares. Common in fir woods. Dangerous.
Lactarius volemus Fries, a tawny yellow-capped mushroom with white gills changing to a yellowish hue, and copious sweet white milk, belongs also to the latter subdivision. Edible.
Russula (Fragiles) emetica Fries. Cap fleshy, at first convex, then expanded or depressed, smooth, polished, red, margin sulcate; gills free, equal and broad, white; stem solid but somewhat spongy in the center, smooth, short, stoutish, white or stained reddish; flesh white, sometimes slightly tinted red, under the thin red cuticle. The cap of this mushroom varies from a deep rich crimson to a pale pinkish red, being very subject to atmospheric changes. Specimens are often found with the cap washed almost white after heavy rains, or with but a slight red spot in the center. The gills and spores are pure white, and the flesh peppery to the taste. If tasted when raw the juice should not be swallowed.
The variety Clusii has a blood-red cap, pallid yellowish gills, adnexed, becoming adnate. Spores white. In woods. Acrid. The variety fallax is fragile, with dingy reddish pileus and adnexed, distant, whitish gills.
Besides the above mentioned, there are other acrid Russulas and Lactars which are regarded with suspicion, though not as yet satisfactorily tested.