Summary:
Subgenus Russularia. Further confirmation of this species in the Pacific Northwest would be desirable. Features include 1) a moist cap that is ferruginous fading to orange-buff or dull rufous, 2) whitish to pale vinaceous flesh that stains yellow when cut, 3) milk that turns slowly yellow, 4) decurrent, close to crowded, narrow gills, 5) a stem colored as the cap or paler, 6) a slowly slightly peppery taste, 7) growth usually with birch, 8) a whitish to yellowish spore deposit, and 9) microscopic characters including nearly round to broadly elliptic spores with amyloid ornamentation of warts and irregular ridges, and a cap cuticle that is a layer of inflated to clavate or irregular cells. The online Species Fungorum, accessed April 2, 2016, says that the name Lactarius theiogalus (Bull.) Gray has been used for Lactarius chrysorheus Fr. and Lactarius tabidus Fr.

Cap:
2-7.5(8)cm across, obtuse to convex with a decurved [downcurved] margin, when old disc depressed and margin spreading, often with low acute umbo; '"ferruginous" to "orange-cinnamon" (ferruginous) to "apricot-orange," fading to "pinkish cinnamon" or finally orange-buff or dull rufous', "azonate or at times faintly zoned"; moist but never viscid, margin bald, faintly striatulate at maturity before fading, (Hesler), 2-7cm across, "shallowly convex becoming flat then funnel-shaped, often with an acute umbo and a spreading margin; dull orangy brown to dark apricot or dull rust, sometimes with faint concentric lines of color; moist, smooth", (Phillips)

Flesh:
firm but brittle; 'dull white to pale vinaceous and usually soon staining yellow when cut', (Hesler), firm but brittle; whitish to pale brownish pink, staining yellow when cut, (Phillips), MILK white, usually staining yellow slowly (the time required much longer than for the change on the flesh), stains white paper yellow, (Hesler), 'white, scant, turning yellow slowly', (Phillips)

Gills:
decurrent, close to crowded, with many tiers of subgills, gills narrow; ''"pale pinkish buff" becoming darker and spotted with "onion-skin pink,"'' when old darker and more orange-cinnamon but always spotted in addition, (Hesler), ''decurrent, crowded, narrow; pale yellowy or pinky-cinnamon'', becoming darker and pink-spotted when old, (Phillips)

Stem:
4-6cm x 1-1.5cm, equal to widened in lower part, hollow, fragile; colored as cap or paler; hoary at first, strigose at base, (Hesler), 4-6cm x 1-1.5cm, fragile, slightly widened toward base; "same color as cap or paler, staining yellow from the milk; with a bloom at first, stiff, rough hairs at the base", (Phillips)

Odor:
not distinctive (Hesler, Phillips)

Taste:
milk slowly slightly peppery (Hesler), mildly or slowly, slightly hot and peppery, (Phillips)

Microscopic spores:
spores 7-9 x 6-7.5 microns, broadly elliptic to nearly round, amyloid ornamentation "in the form of blunt cones and warts or rather irregular, catenulate ridges connected by fairly fine lines or unconnected", the prominences 0.4-0.8(1.0) microns high; basidia 4-spored, 28-37 x (6)7-10 microns, broadest below apex, yellowish in KOH; pleurocystidia: macrocystidia 48-85 x (5)7-11 microns, fusoid, "content refractive and dingy yellowish in KOH, amorphous", pseudocystidia filamentous, cheilocystidia 30-45 x 5-7 microns, similar to pleurocystidia but smaller; cap trama heteromerous, hyphal incrustations lacking; cap cuticle "a layer of inflated to clavate or irregular cells, the zone several cells deep with occasional filaments projecting from between them or originating from them but no true turf present"; stem cuticle of dry, repent hyphae, rosettes present in cortex, (Hesler), spores 7.5-8.5 x 6.4-7.5 microns, nearly round to elliptic, blunt warts and irregular ridges sometimes connected by five [sic] lines, prominences 0.4-0.9 microns high, (Phillips)

Spore deposit:
white if thin, yellowish in heavy deposits, (Hesler), white to creamy (Phillips)

Notes:
Lactarius theiogalus has been found in eastern North America and AK. It was reported by Kauffman from OR. There are collections from BC labeled as this species at the University of British Columbia.

EDIBILITY

no (Phillips)