Hebeloma spetsbergense Beker & U. Eberh.; Beker, Eberhardt & Vesterholt, Fungi Europ. (Alassio) 14: 180, 2016.

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 spetsbergense Beker & U. Eberh.; Beker, Eberhardt & Vesterholt, Fungi Europ. (Alassio) 14: 180, 2016. Fig. 20

Macroscopic description.

Cap 1.0-2.2 cm in diameter, convex to umbonate, sometimes umbilicate, margin smooth, tacky when moist, occasionally hygrophanous, unicolored, sometimes bicolored, at center sepia to fuscous or dark brick, at margin pinkish buff to clay pink to cinnamon, sometimes quite thin margin, without remains of universal veil, partial veil present. Lamellae initially light clay, at maturity slightly more brownish, attachment emarginate, maximum depth 3-5 mm, number of lamellae {L} 18-35, droplets absent, white fimbriate edge sometimes present but weak. Stem (1.5-)1.9-3.1(-3.7) × 0.2-0.3(-0.5) cm, light watery brownish, darker towards base, cylindrical, stem Q (5-)8-12.7(-16.5), fibrillose, usually pruinose at apex. Context firm, stem interior stuffed, later hollow, stem flesh variably discoloring from base. Smell raphanoid sometimes strongly. Taste weakly raphanoid. Spore deposit sepia.

Microscopic description.

Spores amygdaloid, occasionally limoniform, guttulation variable, on ave. 12.0-14.5 × 7.5-8.5 µm, ave. Q = 1.5-1.7, yellow brown to brown, almost smooth to weakly ornamented (O1O2), perispore not loosening (P0), rather strongly dextrinoid (D2D3). Basidia 27-37(-40) × 9-12 µm, ave. Q = 3.3-3.9, mostly four-spored. Cheilocystidia lageniform, ventricose, occasionally with characteristically median wall thickening, some septate, on ave. 45-60 × 4.5-6 (apex) × 4.5-5 (middle) × 8.5-12 (base) µm, occasionally cystidia with yellow contents, ratios A/M = 0.92-1.25, A/B = 0.43-0.61, B/M = 1.87-2.61. Epicutis an ixocutis, 30-35 µm thick (measured from exsiccata), maximum hyphae width 5 µm, without encrustations, shape of trama elements beneath subcutis sausage-shaped, up to 18 µm wide. Caulocystidia similar to cheilocystidia but generally larger.

Collections examined.

W-Greenland: Disko, Fortune Bay, 69.31°N, 53.88°W, 3 Aug 1986, T. Borgen (TB86.121, C-F-103478), 20 m, with Salix glauca in dunes. Qeqertarsuaq/Disko, Godhavn, 69.65°N, 53.32°W, 5 Aug 1986, S.A. Elborne (SAE-86.135-GR, C-F-119733), 0 m, with Salix glauca at lakeside. Kangerlussuaq, just west of Lake Ferguson, 66.99°N, 50.61°W, 6 Aug 2016, T. Borgen (TB16.056G, C-F-103579), 50 m, with Salix glauca and Betula nana in ditch. Kangerlussuaq, Kløftsøerne, 67°N, 50.71°W, 20 Aug 2016, S.A. Elborne (SAE-2016.102-GR, C-F-106740), 270 m, with Betula nana and Bistorta vivipara along lakeside. Kangerlussuaq, Kløftsøerne, 67.03°N, 50.69°W, 19 Aug 2016, H. Knudsen (HK s.n., C-F-108450), 500 m, with Salix sp. and Betula sp. Kangerlussuaq, NE facing slopes along Lake Ferguson, 66.99°N, 50.61°W, 12 Aug 2016, H. Knudsen (HK16.071, C-F-104100), 300 m. N-Greenland: Zackenberg, just N of Zackenberg Hut, 74.5°N, 21°W, 9 Aug 1999, T. Borgen (TB99.256, C-F-119757), 50 m, with Salix arctica , Bistorta vivipara and Sphagnum in scrubland. E-Greenland: Jameson Land, Constable Pynt, Draba Sibirica Elv, 10 km from coast, 71.03°N, 24.23°W, 23 Jul 1983, D. Boertmann (DB GR 83-62, C-F-119801), 50 m, with Salix arctica along riverside. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 12 Aug 2017, T. Borgen (TB17C.113, C-F-106781), 40 m, with Bistorta vivipara in heathland. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 9 Aug 2017, S.A. Elborne (SAE-2017.174-GR, C-F-106764), 40 m, with Salix arctica along riverside. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 2 Aug 2017, S.A. Elborne (SAE-2017.043-GR, C-F-106760), 200 m, with Salix arctica in bog. Jameson Land, Nerlerit Inaat/Constable Pynt, near airstrip, 70.74°N, 22.64°W, 6 Aug 2017, T. Borgen (TB17C.050, C-F-106774), 50 m, with Salix sp. in fen.

Distribution.

Recently described from high arctic Svalbard ( Beker et al. 2016). The eleven Greenland records indicate that it is quite common in the High Arctic zone in Greenland north of 67°N. Circumpolar, High Arctic.

Habitat and ecology.

Twelve collections, four recorded with Salix arctica , four with S. glauca , two with Salix spp., one with Betula nana and one with Bistorta vivipara . Bistorta is often present near collections of mycorrhizal fungi, but only when it was the only possibility was this host recorded. In the Rocky Mountains, Cripps et al. (2019) reported two collections growing with S. glauca and S. arctica . In Greenland, H. spetsbergense is growing both in acid and calcareous habitats, most often in humid localities like bogs, riversides and ditches. The five collections from Svalbard, including the type, are from localities on base-poor ground with S. polaris ( Beker et al. 2016).

Hebeloma sect. Denudata (Fr.) Sacc.; Fl. Ital. Crypt. I 15: 691, 1916.

Veil absent. Cap uni- or bicolored. Lamellae often exuding small hyaline or colored drops. Cheilocystidia long, swollen in the apical part, constricted in the median part, basal part swollen or not. Spores amygdaloid to limoniform, ornamented, sometimes strongly.

Hebeloma subsect. Crustuliniformia Quadr.; Doc. mycol. 14: 30, 1985 ( “1984”).

Cheilocystidia distinctly broadened at apex, base ± cylindrical, wall not thickened. Lamellae edge often with exuded drops.

Figures

Figure 20. Hebeloma spetsbergense A HK 16.071, photograph H. Knudsen B distribution of cited collections C spores x 1600 and D cheilocystidia x 1000 of HK 16.071 in Melzer's reagent. Scale bars: 5 µm; microphotographs H. K. J. Beker.