Brittonia 12: 319. 1960.
Common Name: none
Cap 6-13 cm broad, convex, becoming shallowly infundibuliform; margin inrolled when young, sometimes slightly pubescent, but smooth in age; surface viscid, a mixture of yellow tones arranged in faint concentric bands; flesh, thick, white, firm; odor indistinct, taste very peppery.
Gills decurrent, crowded, narrow, white becoming yellow-buff, bruising yellowish; latex white, usually unchanging, but sometimes pale yellow.
Stipe 2-5 cm tall, 1.5-2.5 cm thick, equal to tapered at the base, at first solid, then hollow, whitish at the apex, ochraceous-brown elsewhere, with darker yellow-brown spots (scrobiculations); veil absent.
Spore 7-10 x 6-8 µm, elliptical with reticulate, amyloid ornamentation; spore print white to pale yellow.
Solitary to gregarious in mixed hardwood/conifer woods; common locally under Quercus (oaks) and Salix (willows); fruiting from early fall to mid-winter.
Inedible; intensely peppery.
Lactarius alnicola is distinguished by a viscid, vanilla-colored, slightly zonate cap, white, usually unchanging latex and a yellow-brown spotted stipe. It is rather common in our area under Quercus agrifolia (coast live oak) where inexperienced collectors sometimes mistake if for the yellow chanterelle, Cantharellus cibarius. It is a mistake made only once as the taste is unforgettably peppery. Ironically, despite its species name, Lactarius alnicola is not common under alder.
Methven, A.S. (1997). The Agaricales (Gilled Fungi) of California. 10. Russulaceae II. Lactarius. Mad River Press: Eureka, CA. 79 p.
Hesler, L.R. & Smith, A.H. (1979). North American Species of Lactarius. University of Michigan Press: Ann Arbor, MI. 841 p.