Hebeloma alpinicola A.H. Sm., V.S. Evenson & Mitchel, Veiled species of Hebeloma in the western United States (Ann Arbor): 48 (1983)

Cripps, Cathy L., Eberhardt, Ursula, Schuetz, Nicole, Beker, Henry J., Vera S. Evenson, & Horak, Egon, 2019, The genus Hebeloma in the Rocky Mountain Alpine Zone, MycoKeys 46, pp. 1-54 : 28

9. Hebeloma alpinicola A.H. Sm., V.S. Evenson & Mitchel, Veiled species of Hebeloma in the western United States (Ann Arbor): 48 (1983) Figures 6B, 15, 23 (9)

Etymology.

alpini- and cola, meaning dweller, to emphasise its alpine habitat, although this taxon is not found exclusively in such habitats.

Description.

Cortina present. Pileus robust, fleshy, 20-40 mm in diameter, irregular convex, somewhat domed or not, reddish brown center with grayish tones, outwards ocher and lighter towards margin (buff not white), not particularly two-toned, with hoary canescent coating that dries shiny; margin turned in at first, and then turned down. Lamellae narrowly attached, slight emarginate, or with a tooth, or pulling away, somewhat broad, milk coffee, L = 36-44; edges white floccose. Stipe 30-40 × 5-10 mm, equal, straight or not, whitish and pruinose at apex, dingy ocher and longitudinally fibrillose and striate in lower part, base sometimes encased in sand or earth. Context dingy whitish, darker below, and flesh staining brown; stipe solid or slightly hollow. Odor raphanoid. Exsiccate: pileus and stipe medium ochraceous brown; lamellae dark brown; stipe base encased in soil in the large collection (CLC1577).

Basidiospores elliptical, or some slightly amygdaliform or ovoid, with rounded end, smooth to slightly rough (O0, O1), small apiculus, not guttulate, not dextrinoid (D0), perispore not loosening (P0), 8-11 × 5-6, on average 9.1 × 5.6 µm, Q = 1.63 Basidia clavate, four-spored, 30-35 × 7-8 µm. Pleurocystidia usually absent but occasionally present, sometimes rostrate. Cheilocystidia mostly cylindrical for the top two thirds and then swollen near the base (lageniform or ventricose), 30-70 µm long × 3-8 µm at apex, 3-7 µm in middle, and 6-11 µm at base, no yellow contents noted. Epicutis thickness up to 200 µm, with no encrusted hyphae recorded.

Rocky Mountain ecology.

Collected from two different sites, one in Montana, the second in Colorado. The first site is a mixture of Dryas , Salix planifolia and S. reticulata , with some Persicaria present. The second site is a low alpine zone with dwarf willows. In both cases the growth habit was gregarious, sometimes in rings, sometimes cespitose, but not completely joined.

Rocky Mountain specimens examined.

U.S.A. COLORADO: Gilpin County, Roosevelt National Forest, Little Echo Lake shoreline, near dwarf willows, 3500 m, 4 Sept 1999, DBG-F-020565, V.S. Evenson, M. Brown; 4 Sept 1999, DBG-F-020582, V.E. Evenson. MONTANA/WYOMING state line: Beartooth Plateau, 3020 m, with Persicaria , Geum , sedges, grasses, and quite distant S. planifolia , 19 July 2001, CLC1577 (MONT), C. Cripps; Quad Creek, 4 Aug 2008 with Dryas octopetala and S. reticulata , HJB12439, C. Cripps.

Other specimens examined.

See Table 2.

Discussion.

Figure 6B shows H. alpinicola as paraphyletic and closely related but not mixed with species from the H. mesophaeum complex other than H. marginatulum . The H. alpinicola representatives differ by 0-13 [0-2] bp from each other. Based on morphology and ITS results, the types of seven species, namely H. alpinicola , H. chapmaniae A.H. Sm., H. littenii A.H. Sm., H. nigromaculatum A.H. Sm., H. perigoense A.H. Sm., H. smithii = H. angustifolium A.H. Sm. et al. nom. illegit. (the name Hebeloma angustifolium (Britzelm.)Sacc. already existed) and H. subargillaceum A.H. Sm. are synonyms. The inclusion of the seven types increases the absolute intraspecific variation to 0-16 [0-4] bp. The distance from other species of the complex is 3-22 [0-7] bp within the sample. Although H. alpinicola has not yet been fully tested in multilocus analyses, we consider its distinctive morphology combined with the ITS evidence to be sufficient to assign the four RM collections to this species.

This taxon, with its small ellipsoid, indextrinoid spores and ventricose cheilocystidia is a member of H. sect. Hebeloma . Morphologically it is closely related to H. excedens and H. mesophaeum. It is generally more robust than these two species, espe cially the stipe, and the pileus is not as two-toned. Colorado collections were described as having gray tones. While further work is needed to decide whether this really is a species distinct from the other two, the molecular evidence coupled with the morphological evidence suggest this to be the case. We have studied a number of collections, from a variety of habitats within North America that all appear to represent this taxon. Hebeloma chapmaniae , H. littenii , H. nigromaculatum , H. perigoense , and H. subargillaceum were all published by Smith et al. (1983) in the same publication that featured H. alpinicola ; the replacement name H. smithii is later ( Quadraccia 1987). Although there is some molecular variation between these seven collections, it is very small and we see insufficient evidence to separate these species. We have selected the name Hebeloma alpinicola on the grounds that although not all collections are strictly alpine, the majority are at least subalpine.