Summary:
Features include 1) a pale lavender brown to grayish vinaceous or vinaceous brown cap that is subviscid to viscid, either not zoned or slightly zoned, 2) white to cream-colored milk that stains tissues lilac to vinaceous brown, 3) adnate to subdecurrent, close to crowded gills, 4) a yellowish white spore deposit, and 5) microscopic characters, including elliptic spores with amyloid ornamentation that is a broken to partial reticulum up to 0.5 microns high with scattered isolated warts. The description here, derived from Hesler(4), is for var. montanus, their specimens of var. uvidus being limited to eastern North America and Europe. Montoya and Bandala have raised var. montanus to species level as Lactarius montanus (Hesler & A.H. Sm.) Montoya & Band.-Munoz (Mycotaxon 85: 400. 2003). The online Species Fungorum, accessed April 2, 2016, gives the latter as the current name, and MycoBank, accessed the same day, gave them as homotypic synonyms. The photograph of Jens Petersen is not specified as to variety. The Arora description is for Lactarius uvidus group which he describes as fairly common in mixed woods in his area of California. A collection from WA at the University of Washington keyed out to Lactarius uvidus var. acystidiosus. That variety was described from Nova Scotia and lacks macrocystidia in the hymenium: its spores (revived from gill tissue) were elongate-elliptic (9-10.5(12) x 6.5-7.5 microns).

Gills:
adnate, close, narrow; pallid to pale vinaceous buff becoming creamy, "not changing appreciably by old age except where injured and there staining pale lilac to finally vinaceous-brown or darker", (Hesler), adnate to slightly decurrent, close; white to yellowish, injured areas staining purplish, then eventually dingy tan, (Arora), adnate to subdecurrent, close to crowded, broad, seldom forking near stem; yellowish white to orange white, staining grayish magenta where cut, (Methven)

Stem:
3-10cm x 1-1.5cm, brittle, club-shaped becoming equal; pallid to vinaceous buff, staining lilac-vinaceous inside and out, often stained ochraceous around base; dry and hoary when young, (Hesler), 3-8cm x 1-2cm, more or less equal, rigid; "pallid or sometimes tinged cap color, often ochraceous-stained toward base"; "smooth, viscid when moist but soon dry", (Arora), subviscid to viscid (Methven)

Veil:
[none]

Odor:
slight (Hesler)

Taste:
strongly resinous but not peppery, (Hesler), mild to slowly bitter or peppery, (Arora), not distinctive (Methven), bitter (Buczacki)

Microscopic spores:
spores 9-10.5(12) x 7-8(9) microns, elliptic, [amyloid] ornamentation "in the form of a broken to partial reticulum with many free ends of branches, scattered isolated warts and ridges also present", prominences 0.2-0.5 microns high; basidia 4-spored, 52-60 x 9-12 microns; pleurocystidia: macrocystidia 60-90 x 6-10 microns, "narrowly fusoid-acuminate, with 0-1 or more subapical constrictions, projecting, content faintly granular", pseudocystidia not observed, cheilocystidia 30-52 x 4.5-9 microns, similar to pleurocystidia, (Hesler for var. montanus), spores 8-12 x 7-8 microns, elliptic, with amyloid warts and ridges, (Arora), spores (9.5)10-11(11.5) x 7.5-8.5 microns, broadly elliptic to elliptic, amyloid ornamentation a broken to partial reticulum up to 0.5 microns high; cap cuticle "an ixocutis to ixolattice, dextrinoid debris and incrustations present"; stem cuticle a thin ixolattice, (Methven for var. montanus)

Spore deposit:
yellowish white (Arora), ivory to pale cream (Buczacki)

Notes:
Lactarius uvidus var. montanus material was cited from WA, OR, ID, AK, AZ, CO, NM, and WY. There are collections from BC at the University of British Columbia unspecified as to variety.

EDIBILITY

said to be poisonous, avoid all purple-staining milkcaps, (Arora)

Synonyms and Alternate Names:
Lactarius uvidus var. montanus Hesler & A.H. Sm.