Lactarius olympianus Hesler & A.H. Sm.

Barge, Edward G. & Cripps, Cathy L., 2016, New reports, phylogenetic analysis, and a key to Lactarius Pers. in the Greater Yellowstone Ecosystem informed by molecular data, MycoKeys 15, pp. 1-58 : 26

Taxon classification Fungi Russulales Russulaceae

11. Lactarius olympianus Hesler & A.H. Sm. Figure 13

Description.

Pileus 20-100 mm in diameter, depressed–convex to infundibuliform, smooth, viscid, zonate, color alternating between rich and dull orange; margin incurved when young becoming straight to wavy in age. Lamellae adnate, crowded to subdistant, cream to dingy yellow, staining orange–brown in age or where damaged. Stipe 20-50 × 10-25 mm, equal to tapering toward the base, smooth, white, at first with a white bloom, staining dingy orange–brown where damaged, solid, becoming hollow. Context white. Latex white, unchanging, staining lamellae orange–brown. Odor mild. Taste acrid.

Basidiospores 8-11.5 × 7.5-9.5 µm, Q = 1.1-1.3, broadly ellipsoid; ornamentation forming a broken to nearly complete reticulum. Pleuromacrocystidia 20-50 × 3-6 µm, scattered to numerous, fusiform; apex acute to moniliform. Cheilomacrocystidia 20-35 × 3-6 µm, scattered, fusiform; apex acute to moniliform.

Ecology and distribution.

In montane conifer forests in western North America. In the GYE, it occurs in seeps and along streams in the spruce-fir zone possibly always in the presence of Picea engelmannii .

Specimens examined.

U.S.A. MONTANA: Gallatin County, Gallatin Range, Windy Pass Trail, under Picea engelmannii , 4 Aug 2012, EB0114 ( MONT); Madison County, Tobacco Root Mountains, Branham Lakes, under Picea engelmannii , 1 Sept 2014, EB0070-14 ( MONT).

Discussion.

This species is very close to and likely conspecific with Lactarius zonarioides Kühner & Romagn. (Figure 2B), which occurs in similar habitats and was described from Europe ( Hesler and Smith 1979).