Summary:
Subgenus Russularia. Features include 1) a deep red to brownish orange or orange, subviscid to viscid cap, 2) crowded narrow gills that are pale pinkish tan, 3) milk that is white slowly becoming yellow and staining the flesh yellow, 4) a stem that is somewhat paler than the cap and hoary at first, 5) a slowly peppery taste, 6) a cream spore deposit, and 7) a cap cuticle that is an ixotrichoderm arising from an interwoven layer of hyphae that are not inflated. |Barge(1) produced a molecular phylogeny in which the holotype of Lactarius subflammeus falls within a clade of collections identified as Lactarius substriatus and conclude that the two taxa "may be conspecific". They go on to say, with species names italicized, "Molecular phylogenetic analyses ... suggest that L. subflammeus is conspecific with L. substriatus; however, sequencing of the holotype of L. substriatus is needed to confirm this observation."

Cap:
3-7(9)cm across, broadly convex with incurved or inrolled margin expanding to flat or with elevated margin and disc shallowly depressed; deep red to orange red, yellowish along extreme margin, when old, pale and duller overall, not zoned, when perfectly fresh colored scarlet; slimy-viscid, soon dry, even to slightly wrinkled, margin bald to faintly pruinose at first, translucent-striate when old or when moist, (Hesler), 2-5(8)cm across, convex to flat, disc depressed, with or without umbo, margin incurved to downcurved; orange to brownish orange or reddish orange; subviscid to viscid, bald, not zoned, margin translucent-striate to striate, (Methven)

Flesh:
thin, brittle; "light pinkish cinnamon", (Hesler), up to 1cm thick at disc, light orange, unstaining on exposure or slowly staining pale yellow, (Methven), MILK white then slowly turning "straw yellow", especially when young, (Hesler), white, slowly turning yellow on exposure, slowly staining the flesh pale yellow, staining white field labels yellow, (Methven)

Gills:
adnate with a decurrent tooth, decurrent when old, crowded, narrow, 0.2-0.3cm broad, typically horizontal; pale pinkish tan, not changing appreciably when old; edges even, (Hesler), "adnate to subdecurrent, close to subdistant, narrow to broad", forking near stem; light orange, staining grayish orange where cut, edges colored as faces, (Methven)

Stem:
3-6cm x 0.9-1.5cm, "equal, solid, fragile"; "apricot-buff" to "rufous" (color generally a paler tone than cap); hoary-canescent at first, bald but not shining when old, (Hesler), 4-8(10)cm x 0.5-1cm, equal or widening toward base, round in cross-section, stuffed to hollow; grayish orange to brownish orange, pale orange tomentum at base; dry to moist, bald, fibrillose-streaked, not scrobiculate, (Methven)

Veil:
[none]

Odor:
not distinctive (Hesler, Methven)

Taste:
milk bitterish then slowly peppery (Hesler), slowly, mildly peppery, (Methven)

Microscopic spores:
spores 6.5-9 x 6-8 microns, nearly round to broadly elliptic, apiculus small, oblique and inconspicuous, [amyloid] ornamentation in the form of an incomplete reticulum of moderately broad bands and fine lines, these often nodulose, bands and lines with some branches, isolated warts also present, prominences to 0.5-0.7(1.0) microns high; basidia 4-spored, 34-46 x 9-15 microns, colorless in KOH, ventricose near mid-portion at sporulation; pleurocystidia: macrocystidia scattered, (38)55-80 x (3)5-9(12) microns, projecting slightly to prominently, "aciculate to narrowly fusoid, content amorphous and refractive to nearly homogeneous", pseudocystidia filamentous, embedded in hymenium; cheilocystidia 30-40 x 3-5 microns, shape as for macrocystidia; subhymenium of narrow, compactly interwoven zone of branched filaments, "mediostratum of interwoven connective hyphae and lactiferous hyphae, no rosettes noted"; cap trama heteromerous; cap cuticle "a turf (ixotrichoderm) of short gelatinous hyphal ends, simple or branched and arising from a densely interwoven layer of hyphae of about the same diameter which become more enlarged by maturity and give the impression of a region of inflated cells (but not a well-defined layer)"; stem surface "of interwoven, repent, nongelatinous hyphae", (Hesler), spores 7.5-9 x 5.5-6.5(7) microns, nearly round to broadly elliptic, ornamentation amyloid, a broken to partial reticulum 0.5-1.0 microns high; basidia 35-50 x 7.5-10.5 microns; cheilocystidia 30-45(55) x 4.5-7.5 microns, fusoid to fusoid-ventricose, often with one or more subapical constrictions, macrocystidia (50)70-90(105) x 6-9 microns, fusoid to fusoid-ventricose, often with one or more subapical constrictions; cap cuticle "an ixotrichodermium arising from an interwoven layer of filamentous hyphae which may become inflated but do not form a cellular layer"; stem cuticle "a simple cutis with scattered projecting hyphal tips", (Methven)

Spore deposit:
cream (Hesler), white to yellow white (Methven)

Notes:
Material was cited for WA (including the holotype), OR, and CA, (Hesler(4)). There are collections from BC at the Pacific Forestry Centre and at the University of British Columbia labeled as this species.

EDIBILITY

not recommended