Lactarius lanceolatus O.K. Mill. & Laursen

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 : 45-48

Taxon classification Fungi Russulales Russulaceae

24. Lactarius lanceolatus O.K. Mill. & Laursen Figure 26

Lactarius lanceolatus The following description is based on Barge et al. (2016)

Description.

Pileus 10-45 mm in diameter, convex to depressed–convex at first, becoming plane to infundibuliform, with or without a small papilla, smooth, sometimes faintly scaly toward the center, viscid to dry, azonate, deep orange–brown to deep orange when immature becoming light to deep orange, often blotchy; margin incurved to straight when immature, becoming straight to upturned and often slightly wavy when mature, ± slightly crenulate. Lamellae adnate to subdecurrent, slightly crowded, pale cream to pale yellow to pale orange, discoloring brownish orange in age or where damaged. Stipe 10-20 × 2.5-7.5 mm, equal to clavate, smooth, dry, at first covered by faint whitish pubescence, pale orange, discoloring dingy orange to dingy light brown where damaged, hollow. Context pale orange. Latex scarce to undetectable, watery, white, unchanging. Odor mild. Taste mild.

Basidiospores 8-10 × 6-8 µm, Q = 1.1-1.4, broadly ellipsoid; ornamentation forming a broken reticulum. Pleuromacrocystidia 73.5-127 × 6.5-10 µm, scattered to abundant, strongly projecting, fusiform to lanceolate; apex acute to moniliform. Cheilomacrocystidia 35.5-89 × 5-10 µm, sparse to abundant, strongly projecting, conical to fusiform; apex acute to moniliform.

Ecology and distribution.

Widespread in arctic-alpine areas in the northern hemisphere with Salix . In the GYE, it occurs above tree line in alpine areas with Salix reticulata , Salix arctica , and Salix planifolia , late summer.

Specimens examined.

U.S.A. MONTANA: Carbon County, Beartooth Plateau, Highline Trail, among dwarf and shrubby Salix spp., 1 Aug 1997, ZT6214 (MONT); among Salix spp. 7 Aug 1998, ZT6412 (MONT); among Salix reticulata , 20 Aug 1999, CLC1389 (MONT); 5 Aug 2008, CLC2358 (MONT); 27 July 1997, CLC1139 (MONT); Carbon County, Hellroaring Plateau, Hellroaring Creek, among Dryas octopetala and shrubby Salix spp., 8 Aug 2015, EB104-15 (MONT); among Dryas octopetala , shrubby Salix spp. and Salix reticulata , 8 Aug 2015, EB105-15 (MONT); among Betula glandulosa and shrubby Salix spp., 9 Aug 2015, EB103-15 (MONT). WYOMING: Park County, Beartooth Plateau, Solifluction Terraces, among Salix reticulata , 20 July 2001, CLC1578 (MONT); 13 Aug 2007, CLC2319 (MONT); among Salix arctica , Salix planifolia and Salix reticulata , 17 Aug 2013, EB 105-13 (MONT).

Discussion.

Lactarius lanceolatus is closely related to Lactarius aurantiacus , and Lactarius luculentus / Lactarius luculentus v. laetus (Figure 2C). It can be distinguished from Lactarius luculentus / Lactarius luculentus v. laetus in having longer cheilomacrocystidia and an alpine ecology with Salix , whereas the latter occur with conifers. Currently, we are unaware of any solid morphological differences between Lactarius lanceolatus and Lactarius aurantiacus . Lactarius lapponicus (syn.: Lactarius duplicatus ), which occurs in boreal and arctic-alpine areas in the Northern Hemisphere with Betula , and possibly other hosts, is also closely related, yet it features strongly yellowing latex ( Heilmann-Clausen et al. 1998). Other similar orange taxa in western North America such as Lactarius substriatus , Lactarius subflammeus , and Lactarius subviscidus all occur below tree line with conifers, and their distributions seem to be centered along the Pacific Northwest coast ( Hesler and Smith 1979). See comments under Lactarius badiosanguineus for features differentiating Lactarius lanceolatus from that species.