Lactarius badiosanguineus Kuehner & Romagn.

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 : 41-42

Taxon classification Fungi Russulales Russulaceae

21. Lactarius badiosanguineus Kuehner & Romagn. Figure 23

Description.

Pileus 15-70 mm in diameter, broadly convex to depressed–convex to broadly infundibuliform, ± umbonate, subviscid to dry, smooth to wrinkled–veined, typically darker when young, liver colored to deep scarlet red to red–brown to orange–brown to dingy orange, conspicuously lighter (to yellow–orange) toward the margin in age; margin ± striate when wet, slightly incurved to straight when young, remaining straight or becoming slightly wavy in age. Lamellae subdecurrent, crowded to subdistant, cream to creamy yellow to pale tan to pale orange–tan. Stipe 20-70 × 8-13 mm, equal to slightly clavate, smooth, dry, faintly white–pruinose when young, dingy orange to red–orange, solid, becoming hollow. Context pale tan to red–orange. Latex scarce to abundant, white, unchanging. Odor mild. Taste mild to slightly bitter.

Basidiospores 7-9.5 × 6-8 µm, Q = 1.1-1.4, subglobose to ellipsoid; ornamentation forming a broken to nearly complete reticulum. Pleuromacrocystidia 40-90 × 5-10 µm, scattered to numerous, subfusiform; apex obtuse to broadly acute. Cheilomacrocystidia 20-50 × 5-9 µm, scattered to numerous, subfusiform; apex obtuse to broadly acute.

Ecology and distribution.

In Eurasia and North America with Picea . In the GYE, this species occurs in moist areas and along streams (although it can also occur on drier upland sites) in the montane spruce-fir zone, possibly always in the presence of Picea engelmannii , summer to fall.

Specimens examined.

U.S.A. MONTANA: Gallatin County, Gallatin Range, East Fork Hyalite Creek, under Abies lasiocarpa and Picea engelmannii , 25 Sept 2013, EB200-13 ( MONT); under Abies lasiocarpa , Picea engelmannii and Pinus contorta , 24 Aug 2014, EB0062-14 ( MONT); Madison County, Tobacco Root Mountains, Branham Lakes, under Picea engelmannii ; 1 Sept 2014, EB0069-14 ( MONT); Sweet Grass County, Crazy Mountains, Big Timber Creek, under Abies lasiocarpa and Picea engelmannii , 1 Aug 2015, EB094-15 ( MONT).

Discussion.

This is the first report of this species from the GYE under the name Lactarius badiosanguineus . In North American treatments (e.g. Hesler and Smith 1979, Bessette et al. 2009), this species may have gone under the name Lactarius hepaticus Plowr. Previous reports of Lactarius subdulcis (Pers.) Gray from the GYE ( McKnight 1982) likely refer to Lactarius badiosanguineus . The European Lactarius hepaticus has a duller, browner pileus (although it can be deep red), yellowing latex and flesh, an acrid taste, and it associates with Pinus in nutrient-poor, acidic soils ( Kränzlin 2005). The European Lactarius subdulcis has a more orange–brown to brown pileus (although it can be reddish), a mild to unpleasant smell, a bitter–acrid taste, and an association with Fagus ( Heilmann-Clausen et al. 1998, Kränzlin 2005). Phylogenetically, Lactarius badiosanguineus appears to be fairly closely related to but distinct from both Lactarius subdulcis and Lactarius hepaticus (Figure 2C).

Lactarius badiosanguineus is closely related to Lactarius subviscidus Hesler & A.H. Sm., Lactarius sphagneti (Fr.) Neuhoff, and Lactarius fulvissimus Romagn. Lactarius subviscidus features typically smaller, more fragile basidiomes with a more uniformly orange pileus, and latex that stains white paper yellow ( Hesler and Smith 1979); Lactarius subviscidus appears to be confined to the coastal forests of the Pacific Northwest of North America. According to Heilmann-Clausen et al. (1998), the European Lactarius sphagneti features a more distinctly two-toned pileus with a paler margin and darker center (although Lactarius badiosanguineus also often displays this character at least in the GYE) as well as more densely reticulate spores with a stronger amyloid reaction. The European Lactarius fulvissimus typically features basidiomes which are more orange overall, white latex which often turns yellow, basidiospores with an ornamentation of small pointed warts, and an ecology with deciduous trees such as Fagus , Quercus , Tilia , Populus , and Corylus , more rarely with conifers ( Heilmann-Clausen et al. 1998, Kränzlin 2005).

Lactarius badiosanguineus is also very similar to Lactarius atrobadius Hesler & A.H. Sm., reported from the Pacific coastal Picea sitchensis belt in North America. Lactarius atrobadius appears to have darker basidiomes, however, a more in depth molecular and morphological comparison between the two taxa is warranted. Lactarius lanceolatus O.K. Mill. & Laursen is also similar, however it typically produces basidiomes which are overall more orange with larger pleuromacrocystidia (73.5-127 × 6.5-10 µm), and it occurs above tree line with Salix . See comments under Lactarius luculentus v. laetus Hesler & A.H. Sm. for features distinguishing it from Lactarius badiosanguineus .