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Species Information
Summary: Lactarius pallescens is characterized by 1) a viscid cap with variable color (white to grayish yellow, brownish orange, light brown, or with a grayish vinaceous tint), 2) unchanging white milk that stains flesh and gills lilac, 3) a viscid white stem, 4) the cap and stem often staining ochraceous to rusty on injured areas, 5) a mild taste, 6) elliptic spores with amyloid ornamentation consisting of a broken to partial reticulum 0.5-1.0 microns high and some isolated warts, 7) a cap cuticle consisting of an ixotrichoderm to ixolattice, and 8) a stem cuticle consisting of an ixocutis to ixolattice. Var. palmeranus has spores lacking a reticulum or at most obscurely reticulate.
Lactarius pallescens var. pallescens material was cited in the original description from WA, OR, ID (holotype), CA, and Switzerland, (Hesler). It has been reported from BC by Gamiet(2) and there are collections from BC at the Pacific Forestry Centre and the University of British Columbia. Var. palmeranus was described from AK.
Cap: (3)4-10cm across, flat-convex then flat-depressed, margin incurved; milk-white when young, 'slowly becoming "pale vinaceous-fawn" to "light vinaceous-fawn" (a grayish vinaceous tint), becoming grayer on aging', 'at times developing ochraceous to pale rusty stains on aging (especially around injured areas)'; very slimy-viscid and drying slowly, bald, shining when dry, azonate or faintly zoned at times, margin faintly downy, (Hesler), 3-10cm across, broadly rounded to somewhat depressed centrally, edge incurved to downcurved; color milk white at first, "becoming grayish to grayish brown or light brown or slightly lavender", when old with orange yellow stains; slimy to sticky, (Ammirati), color extremely variable, ranging from white to grayish yellow, brownish orange, or light brown depending on environmental conditions; viscid to slimy-viscid, (Methven)
Flesh: white, staining lilac and progressing to lilac-brown finally', (Hesler), white, exuding copious white milk when cut that stains tissue lilac then lilac-brown, (Ammirati), MILK copious; 'milk-white, drying vinaceous-buff and staining tissues lilaceous', (Hesler), copious; white, stains tissue lilac then lilac brown, (Ammirati), white, unchanging, staining flesh lilac on exposure and gills lilac where cut, (Methven)
Gills: adnate to adnate-decurrent, close becoming subdistant, moderately broad; milk-white stained lilac from milk, often ochraceous along edges when old, (Hesler), adnate or slightly decurrent, close to somewhat spaced; white, staining lilac, with orange-yellow stains along edges when old, (Ammirati)
Stem: 3-8cm x 0.9-1.7cm, widening evenly downwards; milk-white, slowly changing as in cap ''and often finally stained ochraceous to rusty brown around the base on injured areas''; ''slimy-viscid when fresh, shiny when dry'', (Hesler), 2.5-12.5cm long, fairly thick; white, color changing like cap; "slimy to sticky then shiny when dry", (Ammirati), subviscid to viscid (Methven)
Veil: [none]
Odor: slight (Hesler)
Taste: very slowly but distinctly slightly peppery, taste of milk not peppery, (Hesler), not distinctive (Methven)
Microscopic spores: spores 9-10.5 x 7-9 microns, elliptic, [amyloid] ornamentation of "short bands and ridges and some isolated warts forming a broken to a partial reticulum", prominences 0.4-1.0 microns high; basidia 4-spored, 50-60 x 9-12 microns; pleurocystidia: macrocystidia 75-110 x 6-15 microns, "fusoid-pointed, rarely subcylindric-acuminate, some with one or more constrictions toward the apex", content granular to +/- banded as revived in KOH, cheilocystidia (37)50-75 x 6-11 microns, otherwise resembling pleurocystidia; cap cuticle an ixotrichoderm in young caps, at maturity an ixolattice, (Hesler), spores (8.5)9-10.5 x 6.5-8(8.5) microns, elliptic, amyloid ornamentation a broken to partial reticulum 0.5-1.0 microns high; cap cuticle an ixotrichoderm "arising from an interwoven layer of filamentous hyphae, often collapsing to an ixolattice, dextrinoid debris and incrustations present"; stem cuticle an ixocutis to ixolattice, (Methven)
Spore deposit: white to creamy depending on thickness of deposit, (Hesler), pale orange in mass (Methven)
Habitat / Range
on soil and humus or on moss in conifer forests, late summer and fall, (Hesler), single, scattered or in small groups, on ground in soil, humus or moss, in conifer or mixed forests, (Ammirati)
Similar Species
Lactarius montanus has 1) darker colors, 2) a cap and stem that are subviscid to viscid, 3) a cap surface staining green in KOH, 4) slightly larger spores (10-11 x 7.5-8.5 microns) with ornamentation up to 0.5 microns high, and 5) a cap cuticle consisting of an ixocutis to ixolattice, (Methven). Lactarius uvidus var. uvidus, found in eastern North America and Europe, has darker colors and a cap that is viscid to slimy: 2.5% KOH stains the cap surface green, (Hesler). In L. uvidus var. uvidus according to Methven(2) amyloid ornamentation of the spores is composed of isolated elements not suggesting a reticulum, and the cap cuticle consists of an ixolattice to an ixocutis. Lactarius californiensis has a dry to moist non-viscid stem, smaller spores (7.5-9 x 6-7.5 microns), a stem cuticle that is a simple cutis, and a cap cuticle that is an ixocutis, whereas L. pallescens var. pallescens has a gelatinized stem cuticle (ixocutis to ixolattice) and the cap cuticle is an ixotrichoderm often collapsing to an ixolattice, (Methven). Lactarius californiensis has a dry stem and hyphae of the cuticular region with scattered incrustations, (Hesler(4) who say however "More data are needed to indicate whether two taxa are involved here or one variable one.")
Hesler(4) (colors in double quotation marks from Ridgway(1)), Trudell(1)*, Ammirati(1)*, Ammirati(5), Gamiet(2) (accessed 23/7/01), Methven(2), Desjardin(6)*, Siegel(2)*, Marrone(1)* References for the fungi
