Lactarius argillaceifolius megacarpus
N. Amer. Sp. of Lactarius, p. 369. 1979.
Common Name: none
Cap 9-21 cm broad, convex-depressed, the margin incurved, often wavy; surface viscid when moist, smooth, obscurely zonate, buff-brown, light grey-brown, sometimes spotted or mottled darker brown, at times tinged lilac, typically lighter at maturity; flesh thick, pallid to cream, unchanging; odor indistinct; taste mildly peppery.
Gills subdecurrent, moderately broad, close to crowded, cream becoming dingy-buff in age; latex white unchanging but discoloring gill tissue grey-brown.
Stipe 7-14 cm tall, 2-5 cm thick, stout, stuffed, more or less equal; surface subviscid to dry, cream, irregularly pale-buff in age; flesh white unchanging; veil absent.
Spores 7-9 µm, round to subglobose with partially reticulate amyloid ornamentation; spore print cream-yellow.
Solitary to scattered under oaks, especially coast live oak (Quercus agrifolia); fruiting from mid to late winter.
Unknown.
Large size and drab coloration characterize Lactarius argillaceifolius var. megacarpus. Lactarius pallescens is similar though usually paler colored, smaller, with a latex that stains gill tissue lilac, not grey-brown. The largest of our local milky caps, Lactarius argillaceifolius var. megacarpus can be common in some years and rare in others.
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Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Hesler, L.R. & Smith, A.H. (1979). North American Species of Lactarius. University of Michigan Press: Ann Arbor, MI. 841 p. (Protologue) (PDF)
Methven, A.S. (1997). The Agaricales (Gilled Fungi) of California. 10. Russulaceae II. Lactarius. Mad River Press: Eureka, CA. 79 p.
Methven, A.S. (1998). Lactarius in California and Beyond: Introduction to Subgenera and Species of Lactarius in California. Privately Published: Charleston, IL. 22 p. (PDF)
Siegel, N. & Schwarz, C. (2016). Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.
