=L. corru´gis= Pk.—having wrinkles or folds. =Pileus= 3–5 in. broad, firm, convex, then nearly plane or centrally depressed, _rugose reticulated_, covered with a _velvety pruinosity or pubescence, dark reddish-brown or chestnut-color_, fading with age to tawny-brown. =Gills= close, dark cream-color or subcinnamon, _becoming paler_ when old, sordid or brownish where bruised or wounded. =Stem= 3–5 in. long, 6–12 lines thick, equal, solid, glabrous or merely pruinose, paler than but similar in color to the pileus. =Spores= subglobose, 10–13µ. =Milk= copious, white, taste mild. Thin woods. Sandlake, Gansevoort and Brewerton, N.Y. August and September. This curious Lactarius is related to L. volemus, from which it may be separated by its darker colors and its corrugated pileus. The flexuous reticulated rugæ present an appearance similar to that of the hymenium of a Merulius. The pileus is everywhere pruinose-pubescent and the gills bear numerous spine-like or acicular cystidia or spicules, 4–5µ long. These are so numerous on and near the edges of the gills that they give them a pubescent appearance. _Peck_, 38th Rep. N.Y. State Bot. I found many at Mt. Gretna, Pa., up to 6½ in. in diameter. Flesh not so firm as L. volemus. Stem equal, rugulose, flattened in old specimens. Milk very slightly acrid. Better in taste and quality than L. volemus. =L. lute´olus= Pk.—yellowish. =Pileus= 2–3 in. broad, fleshy, rather thin, convex or nearly plane, commonly umbilicately depressed in the center and somewhat rugulose, pruinose or subglabrous, buff-color. =Flesh= white, taste mild. =Milk= copious, flowing easily, white or whitish. =Gills= close, nearly plane, adnate or slightly rounded behind, whitish, becoming brownish where wounded. =Stem= 1–1.5 in. long, 3–5 lines thick, short, equal or tapering downward, solid, but somewhat spongy within, colored like the pileus. =Spores= globose, 7.6µ broad. Dry woods. East Milton, Mass. August. _H. Webster._ This species is related to Lactarius volemus and L. hygrophoroides, but its smaller size and short stem will distinguish it from the former and its close gills from the latter. Its paler buff-color will separate it from both. Some specimens have a narrow encircling furrow or depressed zone near the margin and a slightly darker shade of color on the margin. The milk constitutes a remarkable feature of the species. According to the notes of the collector it is exceedingly copious, rather sticky, serous in character with white particles in suspension. It flows from many points as soon as the plant is disturbed and it stains the gills. It is impossible to collect an unstained specimen, so free is the flow of the milk. He, Mr. Webster, says: “I have never succeeded in picking a specimen so quietly as to prevent an instant and copious flow of its milk.” Torrey Bull., Vol. 23, No. 10, 1896. Angora, West Philadelphia, August, 1897. In oak woods. August, September. _McIlvaine._