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

Subgenus Tristes

393

typicum in Herbarium University of Tennessee, 22680; legit L. R. Hesler, Cades Cove, Tennessee, 6 Oct 1957.
Pileus 4-6 cm broad, convex, expanded, slightly depressed, "buffy
brown," viscid, glabrous, azonate, margin incurved then expanded, finally short-striate. Context thick on disc, thin on margin; odor mild.
Latex white, unchanging and not staining, soon moderately acrid.
Lamellae adnate to slightly subdecurrent, white, finally "light
pinkish cinnamon," not staining, close to crowded, lamellulae numerous,
medium broad, narrowed both ways, edges even.
Stipe 5-7 cm long, 10-12 mm thick, dingy brownish to pale cinnamon, dry, base slightly strigose, elsewhere glabrous, equal above the
pointed base, hollow, not spotted.
Spore deposit white. Spores 7.5-9(10) X 6-7.5,u, broadly ellipsoid;
with a distinct plage hyaline in Melzer's; ornamentation in the form of a
broken to partial reticulum, isolated warts' also present along with
crests; prominences 0.2-1.2 pz high.
Basidia 34-38 X 7-10.5 pu, 4-spored. Pleurocystidia: macrocystidia
45-60 X 7-11 Au, fusoid to fusoid-ventricose, acute to mucronate, content
slightly granular; pseudocystidia filamentose, refractive. Cheilocystidia
26-37 X 5-7 u, fusoid to fusoid-ventricose or mucronate, content ~ granular. Gill trama lacking rosettes, lactifers inconspicuous. Pileus trama
heteromerous, lactifers inconspicuous, no dextrinoid or amyloid debris
seen. Cuticle of pileus sharply defined, an ixolattice 60-75 / thick, the
hyphae thin-walled, septate, branched, 3-6 pt wide, slime soluble in
KOH, more stable in Melzer's. Stipe cuticle of repent hyphae slightly
refractive as revived in KOH; cortex of stipe with rosettes.
Habit, habitat, and distribution.-On soil in pine woods, Cades
Cove, Tennessee, collected by L. R. Hesler, 22680, type, October 6,
1957.
Observations.-Because of the absence of incrustations and debris
in the cuticular region of the pileus, we place this species near the end
of subgenus Tristes. It has considerable resemblance to material of L.
imperceptus but has duller pigmentation. It lacks the staining reaction
and dextrinoid debris of L. vietus.
140a. Lactarius fusco-olivaceus var. graveolens var. nov.
Illus. P1. 74.
Pileus 4-7 cm latus, "olive-brown," azonatus, viscidus. Latex albus, constans, lamellas nullo modo tingens, leviter acer. Lamellae pallidae deinde "cinnamon-buff," confertae, angustae. Stipes cum pileo
concolor vel pallidior, siccus. Sporae 7.5-9 X 6-7,u. Specimen typicum