Hebeloma oreophilum Beker & U. Eberh.; Eberhardt, Ronikier, Schuetz & Beker, Mycologia 107(6): 1295, 2016 ( "2015" ).

Eberhardt, Ursula, Beker, Henry J., Borgen, Torbjorn, Knudsen, Henning, Schuetz, Nicole & Elborne, Steen A., 2021, A survey of Hebeloma (Hymenogastraceae) in Greenland, MycoKeys 79, pp. 17-118 : 17

Hebeloma oreophilum Beker & U. Eberh.; Eberhardt, Ronikier, Schuetz & Beker, Mycologia 107(6): 1295, 2016 ( "2015"). Fig. 18

Macroscopic description.

Cap 1.0-3.8 cm in diameter, convex to umbonate, sometimes strongly, margin smooth, often involute when young, tacky when moist, usually not hygrophanous, but we have occasionally seen collections that are, unicolored or variably two-colored, at center dark olive buff to brownish olive to umber to cinnamon or sepia to brick to dark brick to fuscous, sometimes cracked, at margin cream to pinkish buff to clay-pink, sometimes margin very thin, usually pruinose to tomentose, usually with remains of universal veil, partial veil present. Lamellae whitish then pale clay brown, emarginate to broadly adnexed, maximum depth 3-8 mm, number of lamellae {L} 40-48, droplets absent or very small (lens), white fimbriate edge sometimes present. Stem 1.5-7.0 × 0.3-0.65 {median} × (0.3-1.0) {base} cm, at first whitish later brown downwards, apically with whitish fibrillose ring zone, sometimes with indistinct belts, downwards with suggestion of a fibrillose ring, pale sordid brown, pale watery brown, downwards dark brown when rubbed, cylindrical, rarely clavate, stem Q (4.2-)5.5-8.7(-15), pruinose at apex. Context firm, stem interior stuffed, later hollow, stem flesh discoloring from base usually. Smell raphanoid. Taste raphanoid, slightly bitter. Spore deposit brownish olive.

Microscopic description.

Spores amygdaloid, occasionally ovoid or limoniform, usually weakly papillate, on ave. 11.0-14.0 × 6.5-7.5 µm, ave. Q = 1.6-2.1, yellow brown through brown, guttulation variable, almost smooth to weakly ornamented (O1O2), perispore not or somewhat loosening (P0P1), distinctly to rather strongly dextrinoid (D2D3). Basidia (25-)26-33(-36) × 7-9(-11) µm, ave. Q = 3.3-4.9, mostly four-spored. Cheilocystidia lageniform, ventricose, occasionally cylindrical, occasionally with characteristic apical, median or basal wall thickening, geniculate or septate, 42-57 × 4-6 (apex) × 4-6 (middle) × 8-10 (base) µm, sometimes with yellowish contents, ratios A/M 1.03-1.24, A/B = 0.44-0.67, B/M = 1.57-2.4. Epicutis an ixocutis, 40-70 µm thick (measured from exsiccata), maximum hyphae width 5-7 µm, without encrustations, trama elements beneath subcutis cylindrical to sausage-shaped up to 18 µm wide. Caulocystidia similar to cheilocystidia but less ventricose more cylindrical, often multi-septate, up to 120 µm long.

Collections examined.

S-Greenland: Kangilinnguit, 61.14°N, 48.6°W, 20 Aug 1991, T. Borgen (TB91.233, C-F-103487), 25 m, with Alnus alnobetulae . Kangilinnguit at Grønnedal Hut, 61.23°N, 48.08°W, 15 Aug 1985, T. Borgen (TB85.180, C-F-119740), 350 m, with Salix arctophila in Sphagnum . Narsarsuaq, outer part of Hospital Valley, 61.17°N, 45.43°W, 9 Aug 1985, T. Borgen (TB85.061, C-F-103590), 50 m, with Betula pubescens and Salix glauca . Paamiut, 62.01°N, 49.4°W, 12 Aug 1990, T. Borgen (TB90.010, C-F-103558), 25 m, with Salix arctophila and Salix herbacea in snowbed. Paamiut, 62.01°N, 49.4°W, 14 Aug 1990, T. Borgen (TB90.036, C-F-103480), 10 m, with Salix glauca . Paamiut, 62.01°N, 49.4°W, 1 Sep 1986, T. Borgen (TB86.292, C-F-103588), 100 m. Paamiut, 62.01°N, 49.4°W, 5 Aug 1998, T. Borgen (TB98.073, C-F-103509), 35 m, with Salix herbacea in fen. Paamiut, "Peters Fjeld", 62.01°N, 49.4°W, 31 Aug 1983, T. Borgen (TB83.035, C-F-103472), 10 m, with Salix arctophila in Sphagnum . Paamiut, head of Eqaluit, median part, 62.03°N, 49.25°W, 15 Aug 1998, T. Borgen (TB98.120, C-F-103510), 300 m, with Betula glandulosa and Salix glauca in heathland. Paamiut, Kangilineq / Kvaneøen, 61.95°N, 49.47°W, 6 Sep 1984, T. Borgen (TB84.215, C-F-104298), 20 m, with Salix herbacea and Bistorta vivipara in snowbed. Paamiut, Kangilineq/ Kvaneøen, 61.99°N, 49.66°W, 27 Aug 1984, T. Borgen (TB84.184, C-F-103539), 15 m, with Salix glauca . W-Greenland: Kangerlussuaq, Kløftsøerne, 67.03°N, 50.80°W, 31 Jul 2016, T. Borgen (TB16.017G, C-F-103576), 300 m, with Betula nana and Salix glauca , in Sphagnum in scrubland. Kangerlussuaq, Lake Ferguson, Tasersuatsiaq, 66.97°N, 50.70°W, 22 Aug 2016, S.A. Elborne (SAE-2016.134-GR, C-F-106744), 100 m, with Salix glauca in copse. Kangerlussuaq, NE facing slopes along Lake Ferguson, 66.99°N, 50.61°W, 12 Aug 2016, H. Knudsen (HK16.091, C-F-104120), 300 m, in Sphagnum sp. Kangerlussuaq, slopes SW of Lake Ferguson, 66.96°N, 50.69°W, 29 Aug 2018, H. Knudsen (HK18.401, C-F-111120), 380 m, in tundra. N-Greenland: Zackenberg, 74.5°N, 21°W, 17 Aug 2006, T. Borgen (TB06.225, C-F-119772), 20 m, with Salix arctica in scrubland. Zackenberg, Sydkæret, 74.5°N, 21°W, 19 Aug 1999, T. Borgen (TB99.374, C-F-119758), 30 m, with Salix arctica in scrubland. Zackenberg, Sydkæret, 74.5°N, 21°W, 5 Aug 2006, T. Borgen (TB06.098, C-F-119773), 20 m, in fen.

Distribution.

Widely distributed and apparently common in Greenland, but never recorded from the East coast (only north east, see habitat). Described recently ( Eberhardt et al. 2015a) from an alpine site (1970 m) in Slovakia and still only known from few countries. In Europe, it is recorded from northern Finland, from the Subarctic and Arctic zone and from the High Arctic zone on Svalbard. Outside Europe, it is known from low alpine and alpine sites in the Rocky Mountains and Canada ( Beker et al. 2016, Cripps et al. 2019). Circumpolar, arctic-alpine to subarctic.

Habitat and ecology.

Eighteen collections, six recorded with Salix glauca , four with S. arctica , three with S. arctophila , two with S. herbacea and one recorded under Alnus alnobetulae ssp. crispa . The absence from the calcareous, well-investigated Jameson Land on the east coast may signal a preference for more acid soil types. In the low alpine Rocky Mountains, Cripps et al. (2019) found it a number of times with Salix planifolia , S. arctica and S. glauca .

Figures

Figure 18. Hebeloma oreophilum A SAE- 2016.134, photograph S. A. Elborne B distribution of cited collections C spores x 1600 and D cheilocystidia x 1000 of HK 18.401 in Melzer's reagent. Scale bars: 5 µm; microphotographs H. K. J. Beker.