North American species of Lactarius / L. R. Hesler, Alexander H. Smith.

396

North American Species of Lactarius

sidiocarps of var. fagetorum. The taste in var. fagetorum is tardily acrid,
and even thin spore deposits show a tint of yellow.
Material cited.-NEW YORK: Peck, Sandlake, July (type, NYS),
also from Grieg (also marked type, NYS).
141a. Lactarius cinereus var. fagetorum var. nov.
Illus. P1. 75; fig. 229.
Pileus 3-6 cm latus, subplanus, demum late infundibuliformis, viscidus, subnitens, olivaceo-griseus, azonatus. Contextus albidus, mitis.
Latex lacteus, tarde leviter acer, constans. Lamellae decurrentes, albae
demum cremeae, confertae, angustae, non-maculatae. Stipes 4-7 cm
longus, 8-15 mm crassus, pallidus vel cinereus, leviter viscidus mox siccus, cavus. Sporae in cumulis pallide luteae, 6-7.5(8) X 5-6 Pu. Specimen typicum in Herbarium University of Michigan conservatum, Smith
80716, legit prope Cedar Lake, Washtenaw County, Michigan, 5 Oct
1971.
Pileus 3-6 cm broad, nearly plane, with an incurved margin, expanding to shallowly funnel-shaped, viscid, soon dry and somewhat
shining, gray to olivaceous-gray to olive-buff, or in age olive-buff slightly
tinged lilac, pellicle separable, azonate rarely ~ zonate. Context white;
odor slight, taste mild then slightly acrid (test young pilei). Latex milklike, scanty, mild becoming faintly peppery or burning-acrid, unchanging, gills not staining or at times in age brownish spotted.
Lamellae decurrent, crowded, narrow, white, becoming cream
colored, not spotting readily (only in age with brownish spots).
Stipe 4-7 cm long, 8-15 mm thick, pallid to grayish or nearly concolorous with the pileus, thinly viscid at first, soon subshining and dry,
hollow.
Spore deposit pale yellow (against white paper). Spores 6-7.5(8) X
5-6 pi, ellipsoid, plage distinct and hyaline in Melzer's; ornamentation
of isolated warts, short ridges and one or two heavy bands often
branched, all together not forming a reticulum or at best a partial one;
prominences 0.2-0.7,u high.
Basidia + 37-45 X 9 p, 4-spored. Pleurocystidia: macrocystidia
50-80 X 6-9,u, aciculate to fusoid-acuminate, projecting, hyaline, content granular; pseudocystidia apparently absent. Cheilocystidia 22-33
(37) X 4.5-7,u, fusoid-acuminate. Gill trama with inconspicuous lactifers. Pileus trama heteromerous, lactifers inconspicuous; hyphal incrustations observed in young specimens. Pileus cuticle (in young pilei)
an ixotrichoderm which consists of branched narrow (2-4 pu) hyphae embedded in slime, this layer collapsing to an ixolattice and in old speci