Cap 0.9–21 cm, convex or more rarely campanulate or applanate, rarely depressed at center, dry, in wet weather viscid in some species, or tacky, smooth or rarely scaly, margin even or undulate, smooth, rarely hygrophanous, rarely striate, several shades of brown, from whitish to pale beige to dark brown, occasionally orange-brown, rarely reddish brown, along margin with or without remnants of universal veil, floccose or velutinate. Lamellae emarginate to adnate, thin, unicolored, at first pale, at maturity browner, in some groups with hyaline or brown droplets along margin. Stem 2.0–14.0 × 0.1–2.0 cm, cylindrical or bulbous at base, occasionally rooting, at first white, whitish or cream, becoming pale ochraceous to brown or even black, white tomentose, floccose or pruinose, rarely velutinate, some groups with partial veil, rarely with a membranous ring. Flesh color resembling the color of the stem, often discoloring brownish from stem base when bruised or old. Smell often radish-like, in one section sweetish, in some species insignificant. Taste mild to bitter, rarely significant. Spore deposit umber to dark cinnamon or dark brick red.

Spores most often amygdaloid, also ellipsoid or limoniform, rarely fusoid or navicular, in some species distinctly papillate, from pale yellow to dark brown, almost smooth to distinctly verrucose and ornamented with separate or coherent irregular warts, in some groups with ± loosening perispore, in Melzers solution from indextrinoid to distinctly and strongly dextrinoid. Cheilocystidia present in all species, variable but distinctive, cylindrical, lageniform, slenderly clavate, spheropedunculate, ventricose or balloon-shaped or variations thereof, rarely forked, in some species partially thick-walled, straight, sinuate or geniculate, hyaline or pale brown. Pleurocystidia rarely present, when present usually similar to cheilocystidia. Caulocystidia present in all species, similar to cheilocystidia, often fasciculate. Basidia cylindrical to slenderly clavate, 4-spored, rarely also 2-spored, in one arctic species only 2-spored. Pileipellis an ixocutis, a thin layer of narrow, hyaline hyphae, smooth or encrusted, 30–250 µm thick.

Hebeloma is a genus of ectomycorrhizal fungi. The symbionts belong to a wide variety of families of dicotyledons. In Greenland, according to the observations of T.B., S.A.E. and H.K.K. symbionts appear to belong to the families: Salicaceae, Betulaceae, Polygonaceae and Rosaceae. The total list consists of only 11 species: Salix glauca, S. herbacea, S. arctica Pall., S. arctophila, Betula pubescens var. pumila, B. nana., B. glandulosa, Alnus alnobetula subsp. crispa, Bistorta vivipara, Dryas octopetala and D. integrifolia.

Bistorta vivipara (L.) Delarbre (≡ Polygonum viviparum L., Polygonaceae) has often been observed close to species of Hebeloma and Brevik et al. (2010) isolated sequences of Hebeloma spp. from its roots in Spitsbergen, which is normally considered as a strong indication that this plant associates with the respective fungus. In a few cases, T.B. found rhizoids from Hebeloma attached to the roots of Bistorta, but found it difficult to rate the importance of these observations, since there have often been other possible hosts observed nearby. For Alnus, there is no evidence that it is a host; for the few records from Alnus-shrubs, it is not possible to rule out nearby willows or birches. The remaining perennial shrubs in Greenland, Sorbus groenlandica (C.K. Schneid.) Á. Löve & D. Löve and Juniperus communis L. do not form ectomycorrhiza. This is also the case for members of the heather family (Ericaceae) that occur in Greenland, with the rare exception of Arctostaphylos alpina.

Cap 1.2–4.5 cm in diameter, robust, fleshy, irregularly hemispherical to convex, somewhat domed or not, almost unicolored, center cinnamon to dark pinkish buff, dark olive buff or rarely umber, sometimes with grayish tones, outwards ocher and lighter buff not white towards margin, sometimes with hoary canescent coating that dries shiny, with weakly hygrophanous spots, dry, margin inrolled at first, and then turned down, partial veil present. Lamellae narrowly attached, slightly emarginate, or with a tooth, or pulling away, somewhat broad (2‒5 mm), pale gray brown to milky coffee, number of lamellae {L} 30–44, edges white floccose, without watery droplets. Stem 1.5–7.0 × 0.2–0.8 cm, cylindrical, whitish pruinose at apex, often with a whitish ring zone, dingy ocher to sordid yellowish or fairly dark brown, longitudinally strongly fibrillose and striate in lower part, often darkening when bruised, base sometimes encrusted with sand or earth, solid or slightly hollow. Context dingy whitish, darker below, unchanging or flesh staining brown. Smell weakly raphanoid. Taste almost insipid to slightly bitter. Spore deposit near fulvous.

Figure 7. 

Hebeloma alpinicola A HK18.322, photograph H. Knudsen B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of HK18.322 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores ellipsoid or some slightly amygdaliform or ovoid, with rounded end, apiculus small, on ave. 8–10.5 × 5–6 µm, ave. Q = 1.55–1.85, smooth to slightly rough (O1), not guttulate, not or very slightly dextrinoid (D0 D1), perispore not loosening (P0). Basidia clavate, mostly four-spored, 20–35 × 6–8 µm. Cheilocystidia lageniform or ventricose, on ave. 35–55 × 5–6.5 (apex) × 4.5–6.5 (middle) × 6.5–10 (base) µm, occasionally geniculate or bifurcate, sometimes septate. Ratios A/M = 0.95‒1.24, A/B = 0.54‒0.88, B/M = 1.43‒2.17. Epicutis an ixocutis, up to 200 µm thick, maximum hyphae width to 8 µm, encrusted hyphae not seen, shape of trama elements beneath subcutis cylindrical. Caulocystidia similar to cheilocystidia, but generally larger.

S-Greenland: Kangilinnguit, 61.23°N, 48.07°W, 12 Aug 1985, T. Borgen (TB85.099, C-F-5082), 95 m, with Salix glauca and Chamaenerion latifolium in heathland. Kangilinnguit, 61.23°N, 48.10°W, 6 Aug 1984, T. Borgen (TB84.063, C-F-103534), 25 m, with Salix glauca in scrubland. Kangilinnguit, 61.23°N, 48.07°W, 17 Aug 1985, T. Borgen (TB85.071, C-F-5081), 95 m, with Alnus alnobetulae. Narsarsuaq, 61.15°N, 45.42°W, 9 Aug 2018, H. Knudsen (HK18.010, C-F-111109), 185 m, with Salix glauca and Betula pubescens in scrubland. Narsarsuaq, airport area, 61.08°N, 45.26°W, 3 Aug 1984, T. Borgen (TB84.028, C-F-103559), 20 m, with Salix glauca and Betula glandulosa in scrubland. Paamiut, 62.01°N, 49.4°W, 1 Aug 2000, T. Borgen (TB00.049, C-F-103516), 10 m, with Salix herbacea in snowbed. Paamiut, 62.01°N, 49.4°W, 8 Aug 1981, T. Borgen TB81.111, C-F-103554), 25 m. Paamiut, 62.01°N, 49.4°W, 20 Aug 1985, T. Borgen (TB85.218, C-F-103532), 30 m, with Salix herbacea and Bistorta vivipara in snowbed. W-Greenland: Kobbefjord, NuukBasic Station, 64.078°N, 51.23°W, 25 Aug 2018, H. Knudsen (HK18.322, C-F-111116), 5 m, with Salix herbacea in tundra. Sisimiut, Kællingehætten, 66.93°N, 53.59°W, 16 Aug 2016, H. Knudsen (HK16.165, C-F-108401), 400 m. N-Greenland: Zackenberg, Ulvehøj, 74.47°N, 21°W, 7 Aug 1999, T. Borgen (TB99.238, C-F-119805), 40 m, with Salix arctica and Bistorta vivipara. E-Greenland: Kuummiut, Torsukattak, 65.87°N, 37.01°W, 2 Aug 2008, T. Borgen (TB08.039, C-F-101623), 35 m; with Salix glauca in heathland. Kuummiut, Torsukattak, 65.87°N, 37.01°W, 2 Aug 2008, T. Borgen (TB08.037, C-F-101621), 35 m.

Widely distributed in Greenland, only missing in Constable Pynt. Originally described from the Seven Devils Mountains in Idaho, North America by Smith et al. (1983), more recently from the Rocky Mountains by Cripps et al. (2019) and from the European Alps by Grilli et al. (2020). This species appears to favor both boreal and arctic or alpine habitats. Most collections from Rocky Mountains were from subalpine areas. In Greenland, it occurs from the Subarctic zone to the High Arctic zone, and the Greenland collections from Zackenberg are the northernmost known (74.47°N). Circumpolar, arctic-alpine.

Thirteen collections in all, mainly with Salix glauca in scrubs and heathland, three collections in snowbeds with S. herbacea, one collection with S. arctica, and one collection with Alnus alnobetulae ssp. crispa, but the presence of other possible associates should not be ruled out. In the Rocky Mountains, Cripps et al. (2019) found two collections, one with Dryas, Salix planifolia Pursh. and S. reticulata L., the other subalpine record with dwarf willows only. Hebeloma alpinicola seems not to be specific regarding soil conditions.

Cap 1.0‒4.1 cm in diameter, convex, sometimes umbonate, margin involute, rarely sulcate, tacky when moist, sometimes hygrophanous, uniformly colored or variably bicolored, at center umber to sepia (6E6, 6E7, 6F6, 6F7), margin cream to pinkish-buff to ochraceous or dark olive buff (4A2, 4A3, 5A3, 5B3, 5B5, 5C5); remains of universal veil sometimes present; partial veil present. Lamellae adnate or adnexed to emarginate, pale brown, maximum depth 3‒5 mm, number of lamellae {L} 40‒48, droplets usually absent, but occasionally visible with × 10 lens, white fimbriate edge usually present, but sometimes indistinctly. Stem 1.3‒7.0 × 0.3‒0.6 cm, 4.5‒7.3(–8) cm at base, stem Q 3.3‒15.5(–18), at first whitish fibrillose becoming pale brown, base cylindrical to clavate or bulbous, usually pruinose or floccose at apex. Context firm, stem inside stuffed, later hollow, stem flesh discoloring from base, sometimes weakly. Smell raphanoid, sometimes with hints of cocoa. Taste mild to bitter, usually raphanoid. Spore deposit brownish olive (5E5).

Figure 8. 

Hebeloma clavulipes A JV02-517 (from Denmark), photo J. Vesterholt, reproduced by kind permission from Beker et al. (2016) B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of TB90.100 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores amygdaloid or limoniform, occasionally appearing ovoid or fusoid, on ave. 10.5‒12.5 × 6.0‒6.5 µm, ave. Q 1.6‒2.1, very weakly ornamented (O1 O2), perispore not or somewhat loosening (P0 P1), rather strongly dextrinoid (D2 D3), yellow to yellow brown, ± guttulate, papillate. Basidia 23‒32(‒36) × 7‒10 µm, ave. Q = 2.6‒4.4, mostly four-spored. Cheilocystidia lageniform to ventricose, occasionally cylindrical, occasionally with a characteristic thickening, apically, basically or medially, sometimes geniculate or septate, on ave. 41‒60 × 4.5‒6 (apex) × 4‒5.5 (middle) × 7.5‒12 (base) µm, ratios A/M = 0.93‒1.25, A/B = 0.45‒0.76, B/M = 1.58‒2.31. Epicutis an ixocutis, 125–170 µm thick (measured from exsiccata), maximum hyphae width 3.5‒7 µm, sometimes encrusted, shape of trama elements beneath subcutis sausage-shaped, up to 14 µm wide. Caulocystidia similar to cheilocystidia, but usually less ventricose, up to 120 µm long.

S-Greenland: Paamiut, W of the Navigation School area, 62°N, 49.67°W, 7 Sep 1990, T. Borgen (TB90.100, C-F-119760), 20 m, with Salix herbacea.

Only one record and apparently a very rare species in Greenland recorded only once during the 20 years when Borgen regularly collected in Paamiut. The general distribution in Europe (Beker et al. 2016) is from the Temperate zone to southern Boreal and Subalpine zone up to 1700 m. The Greenland record is the northernmost known (62.00°N). Temperate, boreal, subarctic, and now also from Low Arctic zone.

Only one collection, with Salix herbacea. In Europe, the hosts are Betula, Picea and Salix (Beker et al. 2016), but the associated Salix species are of the shrub-like kind, like S. aurita.

Cap 2.5–7.5 cm, convex to irregularly gibbous, sometimes broadly umbonate, with incurved later straight, opaque margin, occasionally appendiculate, dry and dull, unicolored mainly sepia, sometimes with light grayish adpressed covering. Lamellae almost free to emarginate gray (olive) brown, edge entire, slightly tomentose, number of lamellae {L} 45–58. Stem whitish pale fibrillose, sordid gray-brown, often more or less buried in sand with a sand bulb around the base, cortina pale. Context initially fairly thick, with cavity, firm watery grayish in pileus, pale brownish in stipe to near buff, towards base dark, sordid brown. Smell weakly and indistinctly raphanoid. Taste similar, mild. Spore deposit color not recorded.

Figure 9. 

Hebeloma colvinii A HK16.005, photograph H. Knudsen B distribution of cited collections; C spores ×1600 and D cheilocystidia ×1000 of HK16.005 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores ellipsoid, often ovoid or amygdaloid on ave. 12.0‒14.5 × 7.5‒8.5 µm, ave. Q 1.5‒1.9, very weakly ornamented (O1 O2), perispore not noticeably loosening (P0), indistinctly dextrinoid (D0 D1), yellow brown, ± guttulate, not papillate. Basidia 26‒42 × 7‒11 µm, ave. Q = 3.0‒4.2, mostly four-spored. Cheilocystidia lageniform to ventricose, occasionally cylindrical or clavate-ventricose, occasionally with a characteristic wall thickening, apically, basically, sometimes septate, on ave. 40‒50 × 5.5‒8 (apex) × 5‒9 (middle) × 10‒13 (base) µm, ratios A/M = 0.90‒1.26, A/B = 0.46‒0.77, B/M = 1.40‒2.45. Epicutis an ixocutis, up to 120 µm thick (measured from exsiccata), maximum hyphae width 10 µm, sometimes encrusted, shape of trama elements beneath subcutis sausage-shaped, cylindrical or ellipsoid. Caulocystidia similar to cheilocystidia, but usually less ventricose, up to 130 µm long.

S-Greenland: Narsarsuaq, 61.16°N, 45.43°W, 31 Aug 2002, T. Borgen (TB02.166, C-F-106756), 30 m, with Salix glauca in riverbed. W-Greenland: Kangerlussuaq, Sandflugtsdalen, 67.13°N, 51.16°W, 7 Aug 2016, T. Borgen (TB16.075, C-F-103585), 50 m, with Salix glauca at riverside dune. Kangerlussuaq, Sandflugtsdalen, 67.06°N, 50.46°W, 7 Aug 2016, H. Knudsen (HK16.008, C-F-104038), 200 m, with Salix glauca. Kangerlussuaq, Sandflugtsdalen, 67.06°N, 50.46°W, 7 Aug 2016, H. Knudsen (HK16.005, C-F-104035), 200 m, with Salix glauca. Kangerlussuaq, southeast of Sugar Loaf, 66.989438°N, 50.548760°W, 25 Aug 2015, S.A. Elborne (SAE-2016.188GR, C-F-107346), 50 m with Salix glauca at riverside dune.

Known from a few collections from three localities in southwestern Greenland. H. colvinii was described by Peck (1875; effectively published 1876) from West Albany in North America. He found it in drifting sand in West Albany near Albany, N.Y. State. Later Kauffman (1918) reported this or a very similar species from New Richmond in Michigan, as did Ritchie (1946) from Lewes, Delaware Bay. Neither of these two collections has been examined as part of this study.

Five collections, all with Salix glauca in pure sand along a river. In one of the localities, Sandflugtsdalen (“valley of driftsand”) at Kangerlussuaq, it was very common and scattered over a large area. The sand is mineral-rich due to mixing with loess.

Hebeloma colvinii was originally described as “Agaricus colvini” (Peck 1875). The name is currently not in use, e.g. there are no records on Mushroom Observer (https://mushroomobserver.org/, accessed 23 Sept 2020) and while Mycoportal (https://mycoportal.org/portal/collections/list.php, accessed 2 Dec 2020) has 63 records, the most recent is from 1972. The identification of the Greenland collections is supported by unpublished studies of type material. It appears that exposed expanses of sandy soil are the characteristic habitat for the species, which is morphologically similar to a number of species of the difficult group around H. dunense and H. mesophaeum. Hebeloma colvinii can be recognized by its large ellipsoid spores, reminiscent of Hebeloma psammophilum, which is currently known only from western Europe (Beker et al. 2016).

Cap 1.0–7.0 cm in diameter, convex to umbonate, sometimes papillate, sometimes umbilicate, margin often involute when young, sometimes scalloped or serrate, becoming wavy or upturned with age, sometimes fibrillose along margin, tacky when moist, sometimes but not consistently hygrophanous, uniformly colored or variably bicolored, at center clay buff, dark olive buff, ochraceous or yellowish brown to brownish olive or umber or sepia to dark brick or orange brown or fuscous, at margin cream to buff or honey to pinkish buff to dark olive buff or yellowish brown to umber or sepia, sometimes with remains of universal veil, partial veil present. Lamellae light gray brown or very pale clay, later brownish clay, adnexed to adnate, usually emarginate, sometimes with decurrent tooth and occasionally decurrent, maximum depth 2.5–9 mm, number of lamellae {L} 20–48, droplets usually absent, but occasionally visible with ×10 lens, white fimbriate edge usually present, but often weak. Stem (1.0–)1.4–8.0 × (0.2–)0.3–1.2 cm, at base 0.2–1.0(–1.2) cm, stem Q = 3.5–15, base cylindrical, sometimes slenderly clavate, occasionally with sand bulb, fibrillose, pruinose or floccose at apex. Context firm, stem interior stuffed, later hollow, occasionally with superior wick, flesh usually discoloring from base, sometimes very strongly. Smell raphanoid, rarely without smell, occasionally hints of cocoa; taste mild to raphanoid to bitter. Spore deposit dark olive buff to brownish olive to umber to fuscous or sepia.

Figure 10. 

Hebeloma dunense A SAE-2017.103, photograph S.A. Elborne B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of SAE-2017.103 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores mainly ellipsoid, some amygdaloid or ovoid, not papillate, 10.0–12.5 × 6.0–7.5 µm, ave. Q 1.5–1.9, very weakly ornamented (O1 O2), perispore not or somewhat loosening (P0 P1), indistinctly dextrinoid (D0 D1), yellow through yellow brown to brown, ± guttulate. Basidia 20–33 × 7–9 µm, ave. Q = 2.8–4, mostly four-spored. Cheilocystidia usually lageniform or ventricose, sometimes cylindrical, occasionally with characteristic wall thickenings, apically, medially or basically, occasionally bifurcate, geniculate, septate (sometimes clamped), subcapitate, 34–57 × 4.5–8 (apex) × 4–7 (middle) × 7–12 (base) µm, with yellow contents, ratios A/M = 0.82–1.43, A/B = 0.42–0.89, B/M = 1.4–2.14. Epicutis an ixocutis, 25–75 µm thick (measured from exsiccata), ixocutis maximum hyphae width 4–8 µm, hyphae occasionally encrusted, shape of trama elements beneath subcutis angular, ellipsoid, isodiametric, spherical or sausage-shaped up to 20 µm wide. Caulocystidia similar to cheilocystidia, but usually more irregular and often multi-septate.

S-Greenland: Kangilinnguit, 61.14°N, 48.6°W, 15 Aug 1985, T. Borgen (TB85.200, C-F-103530), 400 m, with Salix herbacea and Dryas integrifolia in snowbed. Kangilinnguit, 61.23°N, 48.10°W, 8 Aug 1984, T. Borgen (TB84.090, C-F-103535), 25 m, with Salix herbacea along streamside. Kangilinnguit, at Grønnedal Hut, 61.23°N, 48.08°W, 15 Aug 1985, T. Borgen (TB85.183, C-F-103589), 180 m. Kangilinnguit, near Grønnedal Hut, 61.23°N, 48.08°W, 15 Aug 1985, T. Borgen (TB85.186, C-F-103527), 350 m, with Salix arctophila in streamside. Narsarsuaq, 61.08°N, 45.26°W, 1 Aug 1991, T. Borgen (TB91.045, C-F-103486), 100 m, with Salix glauca. Narsarsuaq, 61.17°N, 45.41°W, 17 Aug 2015, H. Knudsen (HK15.078, C-F-8231), 60 m, with Dryas sp. along pathside. Paamiut, 62.01°N, 49.4°W, 12 Aug 1984, T. Borgen (TB84.114, C-F-103536), 10 m, with Salix glauca and Salix herbacea. W-Greenland: Kangerlussuaq, airport area, 67.02°N, 50.72°W, 10 Aug 1986, T. Borgen (TB86.177, C-F-103563), 30 m, with Salix glauca. Kangerlussuaq, near the inland ice, 67.09°N, 50.25°W, 12 Aug 2000, K. Kalamees (HK00.032, C-F-7881), 200 m, in tundra. Kangerlussuaq, Sandflugtsdalen, 67.06°N, 50.46°W, 7 Aug 2016, H. Knudsen (HK16.015, C-F-104045), 200 m, with Salix glauca. Kangerlussuaq, Sandflugtsdalen, c. 15 km E of Base, 67.04°N, 50.53°W, 7 Aug 2016, T. Borgen (TB16.076, C-F-104293), 50 m, with Salix glauca. Kangerlussuaq, Store Saltsø, 66.98°N, 50.6°W, 8 Aug 1986, T. Borgen (TB86.159, C-F-5087), 200 m, with Salix glauca. N-Greenland: Amdrup Land, 80.81°N, 17.32°W, 19 Jul 1993, B. Fredskild (s.n., C-F-7017), 225 m, with Salix arctica in tundra. Blåsø, Kronprins Christians Land, 79.62°N, 23.33°W, 4 Aug 1987, C. Bay (s.n., C-F-6994), 100 m. Prinsesse Dagmars Halvø, Knuths Fjeld, 81.58°N, 16.77°W, 6 Aug 1986, C. Bay (s.n., C-F-4216), 15 m. Zackenberg, at the S bank of Kærelv, 74.5°N, 21°W, 27 Jul 1999, T. Borgen (TB99.114, C-F-119746), 50 m, with Dryas sp. and Salix arctica in scrubland. Zackenberg, in the new delta, 74.5°N, 21°W, 22 Aug 1999, T. Borgen (TB99.411, C-F-119748), 20 m, with Salix arctica in scrubland. Zackenberg, just N of Gadekæret, 74.5°N, 21°W, 5 Aug 1999, T. Borgen (TB99.219, C-F-119752), 20 m, with Dryas sp. and Salix arctica in scrubland. Zackenberg, S of E part of airstrip, 74.5°N, 21°W, 12 Aug 2006, T. Borgen (TB06.159, C-F-119774), 30 m, with Salix arctica in snowbed. Zackenberg, Zackenberg River, 74.5°N, 21°W, 23 Aug 2006, T. Borgen (TB06.263, C-F-119776), 20 m, with Salix arctica in riverbed. E-Greenland: Jameson Land, Constable Pynt, camp N of Katedralen, S of Ugleelv, 70.9°N, 22.92°W, 25 Jul 1989, J.H. Petersen (JHP 89.259, C-F-2561), 170 m. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 12 Aug 2017, T. Borgen (TB17C.118, C-F-106782), 40 m, with Bistorta vivipara and Salix arctica. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76 22.65°W, 4 Aug 2017, T. Borgen (TB17C.037, C-F-106773), 40 m, with Salix sp. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 12 Aug 2017, H. Knudsen (HK17.265B, C-F-105171), 40 m. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 7 Aug 2017, H. Knudsen (HK17.147, C-F-105049), 40 m. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 12 Aug 2017, H. Knudsen (HK17.265A, C-F-105170), 40 m. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 6 Aug 2017, H. Knudsen (HK17.127, C-F-105028), 40 m. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.77°N, 22.67°W, 5 Aug 2017, S.A. Elborne (SAE-2017.103-GR, C-F-106761), 40 m, with Arctostaphylos alpina. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.77°N, 22.73°W, 11 Aug 2017, S.A. Elborne (SAE-2017.219-GR, C-F-106769), 40 m, with Salix arctica at riverside. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv, Harris fjeld, 70.75°N, 22.68°W, 31 Jul 2017, T. Borgen (TB17C.006, C-F-106770), 100 m, with Dryas sp. in heathland. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv, Harris fjeld, 70.75°N, 22.68°W, 3 Aug 2017, H. Knudsen (HK17.070, C-F-1049599, 100 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Gåseelv valley, north side, 70.76°N, 22.69°W, 4 Aug 2017, H. Knudsen (HK17.088, C-F-104984), 160 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 10 Aug 2017, T. Borgen (TB17C.094, C-F-106780), 200 m, with Salix arctica in snowbed. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 2 Aug 2017, T. Borgen (TB17C.030, C-F-106772), 200 m, with Salix arctica. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 2 Aug 2017, H. Knudsen (HK17.043, C-F-104932), 200 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 2 Aug 2017, H. Knudsen (HK17.045, C-F-104934), 200 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 2 Aug 2017, H. Knudsen (HK17.052, C-F-104941), 200 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.7°N, 22.68°W, 2 Aug 2017, H. Knudsen (HK17.056, C-F-104945), 200 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Hareelv, 70.71°N, 22.68°W, 10 Aug 2017, S.A. Elborne (SAE-2017.186-GR, C-F-106765), 200 m, with Salix arctica along streamside. Jameson Land, Nerlerit Inaat/Constable Pynt, middle of Hareelv valley, N side, 70.71°N, 22.73°W, 10 Aug 2017, H. Knudsen (HK17.203, C-F-105108), 320 m. Jameson Land, Nerlerit Inaat/Constable Pynt, Primulaelv, 70.74°N, 22.67°W, 1 Aug 2017, T. Borgen (TB17C.010, C-F-106771), 180 m, with Salix arctica and Bistorta vivipara. Jameson Land, Nerlerit Inaat/Constable Pynt, Primulaelv, 70.74°N, 22.67°W, 13 Aug 2017, H. Knudsen (HK17.282, C-F-105189), 180 m.

Hebeloma dunense is a common and widespread Hebeloma distributed throughout Mediterranean, Temperate, Boreal, Arctic and Alpine areas. It has been recorded in arctic and alpine areas of North America, Europe and Asia (Russia) (Beker et al. 2016). It has one of the most northern records for a Hebeloma at 81.58° in Greenland (Beker et al. 2016). It appears to be one of the most common and widespread of all Hebeloma species in arctic or alpine regions. Circumpolar, Temperate, Boreal, Subarctic and Arctic-Alpine.

Forty-two collections and one of the five most often collected species in Greenland with 11% of the collections. Most are with Salix arctica (10), S. glauca (6), S. herbacea (2), S. arctophila (1) or unspecified Salix in more or less calcareous habitats. The collection from Paamiut was from a man-made area, in this otherwise acid soil locality. Four collections were recorded with Dryas integrifolia and D. octopetala and one with Arctostaphylos alpina (L.) Spreng., although it is possible that some Salix was present. Arctostaphylos alpina is known as a likely mycorrhizal partner for Hebeloma, and has been recorded as the only possible mycorrhizal partner on several occasions (see for example Grilli et al. 2020). In the Rocky Mountains, Hebeloma dunense was recorded as mycorrhizal with S. arctica, S. planifolia and S. reticulata (Cripps et al. 2019). Beker et al. (2016) found the same pattern for hosts; practically all collections were connected to Salix or Populus (Salicaceae), and a few with Dryas in arctic areas. In Beker et al. (2018), reporting on collections from Svalbard, H. dunense was recorded with Salix 91% of the time, with Dryas 16%, with Bistorta 7% (note that more than one possible host was often recorded).

Cap 1.0–4.0 cm in diameter, shallowly convex, campanulate, then almost applanate, broadly umbonate or not, viscid or greasy, with hygrophanous spots, cinnamon to orange-brown or dark brick in center and pale brown on most of the cap, almost unicolored, with or without velar remnants at margin, or with whitish rim, margin originally described as extending beyond the lamellae, thin-fleshed, universal veil sometimes visible on margin edge, partial veil present. Lamellae sinuate, subdecurrent, narrow, becoming broader and eroded, 3.5–5.5 mm broad, without droplets, very pale, cream with pinkish buff tint, number of lamellae {L} 36–48. Stem 1.5–5.0 × 0.2–0.4 cm, equal, slightly curved, pale cream, silky, pruinose above ring zone, dingier to dark brown below, but still pale with golden brown fibrils in zones, blackening towards base, tough, rubbery. Context whitish in cap and stem apex and yellowish brown in lower stem down to blackish at base. Smell raphanoid, rarely odorless. Spore deposit brownish olive.

Figure 11. 

Hebeloma excedens A TB85.238, photograph T. Borgen B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of TB85.238 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores ellipsoid, a few slightly ovoid, not papillate, 8.5–10.5 × 5–6 µm, ave. Q 1.5–2.0, very weakly ornamented (O1 O2), perispore not noticeably loosening (P0), indistinctly dextrinoid (D0 D1), pale yellow, rarely yellow brown, ± guttulate. Basidia 20–33 × 6–8 µm, ave. Q = 3.2–4, clavate, mostly four-spored. Cheilocystidia usually lageniform or ventricose, sometimes cylindrical, occasionally geniculate or septate, subcapitate, on ave. 30–55 × 4–6 (apex) × 4–5 (middle) × 7–9 (base) µm, ratios A/M = 0.96–1.23, A/B = 0.60–0.71, B/M = 1.60–1.82. Epicutis an ixocutis, up to 90 µm thick (measured from exsiccata), ixocutis maximum hyphae width up to 6 µm, hyphae rarely encrusted, shape of trama elements beneath subcutis ellipsoid. Caulocystidia similar to cheilocystidia, but usually larger.

S-Greenland: Paamiut, 62.01°N, 49.4°W, 23 Aug 1985, T. Borgen (TB85.238, C-F-5073), 10 m, with Salix glauca. W-Greenland: Kangerlussuaq near the Ice cap, 67.10°N, 50.23°W, 12 Aug 2000, A-M. Larsen, T. Borgen (TB00.086, C-F-103517), 40 m, with Salix glauca in a copse. Sisimiut, 1 km N of the village, 66.94°N, 53.67°W, 19 Aug 2000, E. Ohenoja (EO19.8.00.20, OULU F050653), 0 m, in heathland.

Known from three localities in southwestern Greenland. Originally described from New York State under Pinus and widespread across North America (Cripps et al. 2019). Similar to H. mesophaeum and therefore likely to be confused and overlooked. Cripps et al. also describe recent records from alpine Rocky Mountains in Colorado and Montana.

Three collections, two of them with Salix glauca. In the Rocky Mountains, S. planifolia was the dominant host (Cripps et al. 2019). Two of the localities are on acid soil.

Cap 0.7–2.5 cm in diameter, convex to umbonate, margin smooth, tacky when moist, not hygrophanous, uniformly colored or more often bicolored, at center sepia to fuscous or dark brick, sometimes with a thin tomentum, at margin dark olive buff to cinnamon or umber; sometimes with remains of universal veil, partial veil present. Lamellae yellowish ochre then brown, emarginate, maximum depth 4 mm, number of lamellae {L} 24–32, droplets absent, white fimbriate edge usually present, but weak. Stem 0.8–7.0 × 0.15–0.5 {median} cm, whitish or pale grayish then browner to gray brown, not darker towards the base, cylindrical, stem Q 4–13, fibrillose, pruinose at apex. Context firm, stem interior stuffed, later hollow, flesh usually discoloring from base. Smell usually raphanoid but sometimes without smell; taste not recorded. Spore deposit color not recorded.

Figure 12. 

Hebeloma fuscatum A SAE-2016.072, photograph S.A. Elborne B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of SAE-2016.072 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores amygdaloid, limoniform, occasionally ovoid, papillate, on ave. 12.5–13.5 × 7.0–7.5 µm, ave. Q = 1.6–1.9, brown, guttulate, almost smooth to weakly ornamented (O1 O2), perispore not or hardly loosening (P0 (P1)), weakly to rather strongly dextrinoid (D2 D3). Basidia 27–33(-36) × 8–9 µm, ave. Q = 3.0–4.1, mostly four-spored. Cheilocystidia usually lageniform or ventricose, occasionally cylindrical, occasionally characteristically with an apical, basal or median thickening, on ave. 41–51 × 4–7 (apex) × 4.5–6 (middle) × 8–13 (base) µm, ratios A/M = 0.9–1.13, A/B = 0.48–0.67, B/M = 1.75–1.97. Epicutis an ixocutis of 30 µm thickness (measured from exsiccata), maximum hyphae width 5–6 µm, sometimes encrusted, shape of trama elements beneath subcutis sausage-shaped and up to 19 µm wide. Caulocystidia similar to cheilocystidia, but less ventricose and very fragile, up to 75 µm long.

S-Greenland: Paamiut, Churchyard, 62°N, 49.67°W, 26 Jul 1985, D. Boertmann (DB 85-21, C-F-119783), 25 m, with Salix glauca. W-Greenland: Kangerlussuaq, SE of Ravneklippen, 67.00°N, 50.67°W, 29 Aug 2018, T. Borgen (TB18.243, C-F-112530), 200 m, with Salix sp. in fen. Sisimiut, Præstefjeld, 66.96°N, 53.74°W, 17 Aug 2016, S.A. Elborne (SAE-2016.072-GR, C-F-106737), 300 m, with Salix herbacea and Bistorta vivipara. Upernavik, 72.79°N, 56.14°W, 18 Aug 2012, D. Boertmann (DB 12.047, C-F-115623), 0 m, in churchyard. E-Greenland: Jameson Land, Nerlerit Inaat/Constable Pynt, around the airport, 70.74°N, 22.64°W, 31 Jul 2017, H. Knudsen (HK17.009A, C-F-104897), 50 m. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.77°N, 22.72°W, 11 Aug 2017, S.A. Elborne (SAE-2017.215-GR, C-F-106768), 40 m, with Salix arctica along riverside. Jameson Land, Nerlerit Inaat/Constable Pynt, Gåseelv valley, north side, 70.76°N, 22.69°W, 4 Aug 2017, H. Knudsen (HK17.091, C-F-104987), 160 m, with Salix sp. in tundra. Jameson Land, Nerlerit Inaat/Constable Pynt, Primulaelv, 70.74°N, 22.67°W, 13 Aug 2017, T. Borgen (TB17C.129, C-F-106783), 180 m, with Betula and Salix in heathland.

Recently described and still only recorded from a few alpine and arctic areas in Europe and arctic Canada (Beker et al. 2016). The Greenland collections are from the Low Arctic zone and High Arctic zone, but the species is rare and scattered. Circumpolar, arctic-alpine.

Eight collections, six with Salix glauca, S. arctica and S. herbacea, two with undetermined Salix sp. The presence of Bistorta and Betula are mentioned, each on one occasion. Soil conditions are variable, but mostly calcareous. Salix was the only host mentioned by Beker et al. (2016). Some recent records from subalpine woodlands in central Europe suggest it may also associate with conifers (Grilli et al. 2020).

Cap up to 1.0 cm in diameter, convex to umbonate, margin usually smooth, but can be crenulate, becoming upturned with age, tacky when moist, with slight spotting, not hygrophanous, uniformly colored or bicolored, at center clay buff or pale yellowish brown or cinnamon, at margin paler, universal veil absent, partial veil present. Lamellae clay color, emarginate to adnate, maximum depth not recorded, number of lamellae {L}18–28; droplets absent, white fimbriate edge indistinct. Stem 1.0–2.0 × 0.2–0.3 cm, ochre-brown, paler in apex, cylindrical, stem Q 6.0–8.5, fibrillose, pruinose at apex. Context firm, stem interior stuffed, stem flesh not discoloring from base. Smell weakly raphanoid or insignificant. Taste not recorded. Spore deposit not recorded.

Figure 13. 

Hebeloma grandisporum A HK17.101, photograph H. Knudsen B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of HK17.101 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores amygdaloid or limoniform, very strongly papillate, on ave. 14–16 × 8.5–9.5 µm, ave. Q = 1.6–1.8, pale brown to yellow brown, weakly guttulate, almost smooth to weakly ornamented (O1 O2), perispore not loosening (P0), distinctly to rather strongly dextrinoid (D2 D3). Basidia 23–44 × 6–10 µm, ave. Q = 3.1–4.3, characteristically 2-spored. Cheilocystidia lageniform or ventricose, occasionally clavate-ventricose, characteristically geniculate and septate, on ave. 40–70 × 5.5–6.5 (apex) × 4.5–5.5 (middle) × 8–10.5 (base) µm, ratios A/M = 1.02–1.44, A/B = 0.53–0.75, B/M = 1.48–2.03. Epicutis an ixocutis, up to 130 µm thick (measured from exsiccata), maximum hyphae width 6 µm, ixocutis hyphae sometimes encrusted, shape of trama elements beneath subcutis isodiametric. Caulocystidia similar to cheilocystidia, up to 120 µm long.

N-Greenland: Zackenberg, Sydkæret, 74.50°N, 20.75°W, 19 Aug 1999, T. Borgen (TB99.376, C-F-104295), 30 m, with Salix arctica. E-Greenland: Jameson Land, Nerlerit Inaat/Constable Pynt, west side of Nathorst Fjeld, 70.76°N, 22.64°W, 5 Aug 2017, H. Knudsen (HK17.101, C-F-104997), 40 m, with Salix sp. in tundra.

Recently described from the southern Carpathians in Romania from a single collection. The two Greenland collections are the first recorded since the type has been published. Both are from the High Arctic zone in Greenland at 70° and 74°N, and it is thus in the northernmost group among the 28 Greenland species. The records are the first from North America and the first outside Europe.

Only two records, both most likely with Salix arctica and both on calcareous soil. The only previous collection, the type, grew with S. retusa L. at 2270 m a.s.l. in the Carpathians (Eberhardt et al. 2015a). Shiryaev et al. (2018) reported from Zmitrovich and Ezhov (2015) the presence of Hebeloma gigaspermum Gröger & Zschiesch. from Franz Josefs Land (Russia). According to Beker et al. (2016), H. gigaspermum is most likely a synonym of H. nauseosum Sacc. Since neither H. nauseosum nor any other species of H. sect. Sacchariolentia occurs in arctic areas, it may be that the large spores and the occurrence in the High Arctic zone rather point to H. grandisporum.

Hebeloma grandisporum is one of the most easily recognized among the arctic-alpine Hebeloma species by the small basidiomes, the large spores, the relatively few, distant lamellae and large, 2-spored basidia. To date, it is the only Hebeloma, of which we are aware, that has consistently 2-spored basidia.

Cap 0.6–3.0 cm in diameter, convex, occasionally umbonate, margin smooth, tacky when moist, not hygrophanous, uniformly colored or bicolored, at center red brown, dark brick, at margin clay-buff, sometimes with whitish fibrils, remains of universal veil variably present, partial veil present. Lamellae at first whitish or pale orange brown, becoming pale cocoa brown, attachment adnate to emarginate, maximum depth not recorded, number of lamellae {L} 23–32; droplets absent, white fimbriate edge usually present, but weak. Stem 2.0–4.3(–5.0) × 0.1–0.45(–0.7) cm, at first whitish, becoming bright orange brown to dirty brown, darker brown towards the base, cylindrical, stem Q (7.1–)10.1–25.8(–35), fibrillose, pruinose to floccose at apex. Context firm, stem interior stuffed, stem flesh discoloring from base. Smell raphanoid, sometimes weakly. Taste mild, raphanoid, later bitter. Spore deposit not recorded.

Figure 14. 

Hebeloma hygrophilum A HK16.195, photograph H. Knudsen B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of HK16.195 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores shape amygdaloid, fusoid or limoniform, papillate, on ave. 11–13 × 6.0–7.0 µm, ave. Q = 1.7–2.0, brown, guttulate, sometimes weakly, weakly to distinctly ornamented ((O1) O2 (O3)), perispore not or somewhat loosening, (P0 P1), distinctly to rather strongly dextrinoid (D2 D3). Basidia 27–32 × 7–9 µm, ave. Q = 3.2–4.2, mostly four-spored. Cheilocystidia lageniform or ventricose, occasionally cylindrical, occasionally with characteristic apical or median wall thickening, geniculate or septate (sometimes clamped), 42–64 × 4.5–5.5 (apex) × 4–5 (middle) × 7–11.5 µm, ratios A/M = 0.89–1.24, A/B = 0.36–0.71, B/M = 1.57–2.52. Epicutis an ixocutis, thickness up to 100–130 µm (measured from exsiccata), maximum hyphae width up to 6–7 µm, ixocutis hyphae sometimes encrusted, trama elements beneath subcutis ellipsoid, sausage-shaped, sometimes cylindrical up to 20 µm wide. Caulocystidia cylindrical to ventricose, multi-septate up to 90 µm long.

S-Greenland: E of Tasiusaq, 61.15°N, 45.60°W, 20 Aug 1993, E. Rald (ER 93.519, C-F-105494), 10 m, in meadow. S of Tasiusaq, 61.13°N, 45.62°W, 23 Aug 1993, E. Rald (ER 93.425, C-F-104549), 0 m. Paamiut, Taartoq/Mørke Fiord, 62.01°N, 49.26°W, 29 Aug 1998, T. Borgen (TB98.234, C-F-103511), 5 m, with Salix glauca in copse. Narsarsuaq, north of Tasiusaq, 60.199186°N, 44.80696°W, 15 Aug 2019, T. Borgen (TB19.052, C-F-137115), 100 m, with Salix glauca in moss on streamside. W-Greenland: Kangerlussuaq, east of Ravneklippen, 67.01°N, 50.66°W, 24 Aug 2016, S.A. Elborne (SAE-2016.168-GR, C-F-106746), 120 m, with Salix glauca along lakeside copse. Kangerlussuaq, Hassells Fjeld, Kløftsøerne, 67.01°N, 50.71°W, 28 Aug 2018, H. Knudsen (HK18.390A, C-F-111118), 300 m, with Salix glauca in bog. Kangerlussuaq, Kløftsøerne, 67°N, 50.71°W, 20 Aug 2016, S.A. Elborne (SAE-2016.105-GR, C-F-106741), 300 m, with Betula nana and Bistorta vivipara along lakeside. Kangerlussuaq, Kløftsøerne, 67.03°N, 50.68°W, 20 Aug 2016, S.A. Elborne (SAE-2016.116-GR, C-F-106742), 300 m, with Salix glauca in copse. Kangerlussuaq, Kløftsøerne, 67.03°N, 50.67°W, 10 Aug 2016, H. Knudsen (HK16.064, C-F-104093), 500 m, in bog. Kangerlussuaq, Kløftsøerne, 67.01°N, 50.71°W, 28 Aug 2018, T. Borgen (TB18.236, C-F-112528), 300 m, with Salix glauca in copse. Kangerlussuaq, N slope towards Lake Ferguson, 66.95°N, 50.72°W, 29 Aug 2018, S.A. Elborne (SAE-2018.429-GR, C-F-115622), 548 m, with Salix arctophila along lakeside. Sisimiut, camping area north of town, 66.94°N, 53.67°W, 20 Aug 2000, S.A. Elborne (SAE-2000.148-GR, C-F-108600), 0 m, with Salix arctophila in bog. Sisimiut, near airport, 66.95°N, 53.67°W, 14 Aug 2016, S.A. Elborne (SAE-2016.005-GR, C-F-106735), 10 m, with Salix sp. in bog. Sisimiut, north of Alanngorsuaq, 66.95°N, 53.55°W, 15 Aug 2016, S.A. Elborne (SAE-2016.022-GR, C-F-106736), 30 m, with Salix sp. in bog. In valley S of Sisimiut behind the dump, 66.93°N, 53.67°W, 18 Aug 2016, H. Knudsen (HK16.195, C-F-108446), 25 m.

Found a number of times in southwestern Greenland. Recently described from subalpine areas in the Pyrenees (France) and known from scattered lowland and montane localities in much of Europe. The northernmost locality is from the Boreal zone in Finland (Rovaniemi) at 66.50°N (Beker et al. 2016), which corresponds well in altitude with Kangerlussuaq and Sisimiut (67°N), but in Greenland these areas are Low Arctic. Hebeloma hygrophilum was recently recorded from alpine North America (Rocky Mountains, Cripps et al. 2019). Circumpolar, arctic-alpine, boreal zone.

Fifteen collections, ten with Salix glauca, S. arctophila or unknown Salix. One collection with Betula nana. Most collections grew in moist habitats often among Sphagnum or the moss Paludella squarrosa (Hedw.) Brid. The same type of boggy localities with Salix planifolia were reported by Cripps et al. (2019) in the Rocky Mountains and by Beker et al. (2016) from Europe, where Salix aurita, S. atrocinerea and possibly more species of Salix act as hosts.

Cap 1.1–4.7 cm in diameter, convex to umbonate, occasionally papillate, margin smooth, tacky when moist, sometimes hygrophanous, uniformly colored or variably bicolored, at center ochraceous or dark olive buff to brownish olive or umber to sepia to fuscous or dark brick, at margin cream to grayish or pinkish buff to ochraceous or dark olive buff to umber, sometimes very thin; with remains of universal veil, partial veil present. Lamellae initially very pale clay, later clay, emarginate, maximum depth 3–8 mm, number of lamellae {L} 32–45, droplets absent, white fimbriate edge usually weakly present. Stem 1.4–4.5(–6.5) × 0.3–0.7(–0.8) cm, pale sordid ochraceous downwards, cylindrical to slightly clavate, fibrillose, whitish pruinose to floccose at apex. Context watery gray brown in cap, in stem lighter, firm, stem interior stuffed, later hollow, occasionally with superior wick, stem flesh usually discoloring from base. Smell usually raphanoid, but sometimes no smell detected. Taste bitter. Spore deposit clay buff to dark olive buff to grayish brown to brownish olive or umber.

Figure 15. 

Hebeloma marginatulum A HK16.082, photograph H. Knudsen B distribution of cited collections C spores ×1600 and D cheilocystidia ×1000 of HK16.082 in Melzer’s reagent. Scale bars: 5 µm; microphotographs H.K.J. Beker.

Spores shape ellipsoid, occasionally amygdaloid or ovoid, on ave. 10.0–13.0 × 5.5–7.5 µm, ave. Q = 1.6–1.9, grayish yellow, rarely guttulate, almost smooth (O1 (O2)), perispore not loosening (P0), not or indistinctly dextrinoid (D0 D1). Basidia (28–)30–34(–37) × 7–9 µm, ave. Q = 4–4.5, mostly four-spored. Cheilocystidia lageniform, ventricose or occasionally cylindrical or clavate, occasionally with characteristic apical thickening, bifurcate, geniculate and septate (sometimes clamped), on ave. 44–69 × 5–7 (apex) × 4.5–5 (middle) × 7.5–10.5 (base) µm, ratios A/M = 1.1–1.4, A/B = 0.53–0.81, B/M = 1.55–2.33. Epicutis an ixocutis, 40–100 µm thick (measured from exsiccata), maximum hyphae width 5–6 µm, variably encrusted, trama elements beneath subcutis ellipsoid, sausage-shaped, occasionally pyriform up to 20 µm wide. Caulocystidia similar to cheilocystidia, but many multi-septate up to 150 µm long.

S-Greenland: Alluitsoq, 60.32°N, 45.27°W, 21 Jul 2003, H.K.J. Beker (HJB10739), 0 m, with Betula sp. and Salix sp. in scrubland. Alluitsoq, 60.32°N, 45.27°W, 21 Jul 2003, H.K.J. Beker (HJB 10742), 0 m, with Betula sp. and Salix sp. in scrubland. Ivittuut, 61.2°N, 48.17°W, 16 Aug 1991, T. Borgen (TB91.198, C-F-103489), 75 m, with Salix glauca in copse. Kangilinnguit, bottom of Laksebund, 61.25°N, 48.08°W, 21 Aug 2018, H. Knudsen (HK18.288, C-F-111113), 100 m, in tundra. Nanortalik municipality, Qinngua valley, 60.14°N, 45°W, 22 Jul 2003, H.K.J. Beker (HJB 10730), 100 m, with Betula pubescens and Salix glauca in woodland. Nanortalik municipality, Qinngua valley, 60.14°N, 45°W, 22 Jul 2003, H.K.J. Beker (HJB 10732), 100 m, with Betula pubescens and Salix glauca in woodland. Narsaq, 60.91°N, 46.05°W, 13 Aug 1993, E. Rald (ER 93.320, C-F-104552), 20 m, with Salix glauca in heathland. Narsaq, 60.91°N, 46.05°W, 2 Aug 1993, E. Rald (ER 93.111, C-F-104312), 20 m, with Salix glauca in heathland. Narsaq, 60.91°N, 46.05°W, 2 Aug 1993, E. Rald (ER 93.112, C-F-106421), 20 m. Narsarsuaq, 61.17°N, 45.42°W, 7 Aug 1985, T. Borgen (TB85.036, C-F-5085), 600 m, with Salix herbacea in snowbed. NE of Nunatoq, 60.27°N, 44.54°W, 22 Aug 1993, E. Rald (ER 93.589, C-F-104554), 0 m. N of Tasiusaq, across the fjord from Narsarsuaq, 61.17°N, 45.61°W, 5 Aug 1992, E. Rald (ER 92.109, C-F-104304), 150 m. Paamiut, 62.01°N, 49.4°W, 20 Aug 1993, T. Borgen (TB93.139, C-F-103495), 50 m, with Salix herbacea in snowbed. Paamiut, 62.01°N, 49.4°W, 23 Aug 1992, T. Borgen (TB92.027, C-F-103493), 10 m, with Salix arctophila and Salix herbacea in fens. Paamiut, 62.01°N, 49.4°W, 23 Aug 1992, T. Borgen (TB92.028, C-F-103492), 10 m, with Salix arctophila and Salix herbacea in tundra. Paamiut, 62.01°N, 49.4°W, 8 Aug 1981, T. Borgen (TB81.109, C-F-103553), 10 m, with Salix herbacea. Paamiut, 61.99°N, 49.66°W, 5 Sep 1986, T. Borgen (TB86.299, C-F-104300), 25 m. Paamiut, 61.99°N, 49.66°W, 4 Aug 1993, E. Rald (ER 93.181, C-F-104314), 25 m, with Salix glauca in heathland. Paamiut, 62°N, 49.4°W, 22 Aug 1986, T. Borgen (TB86.247, C-F-103467), 20 m, with Salix herbacea and Bistorta vivipara. Paamiut Cemetery, 62.01°N, 49.4°W, 19 Aug 1984, T. Borgen (TB84.151, C-F-103538), 10 m, with Salix arctophila. Paamiut, Kangerluarsuk S, 62.28°N, 49.58°W, 31 Aug 1995, B. Knudsen (TB95.068, C-F-103505), 150 m. Paamiut, Kangilineq/Kvaneøen, 61.95°N, 49.47°W, 20 Aug 2008, T. Borgen (TB08.146, C-F-106750), 30 m, with Salix glauca. Qassiarsuk, Tasiusaq, 61.15°N, 45.52°W, 9 Aug 1992, E. Rald (ER 92.181, C-F-104306), 25 m. Qassiarsuk, Tasiusaq, 61.15°N, 45.52°W, 9 Aug 1992, E. Rald (ER 92.180, C-F-104305), 25 m. Tasiusaq, 61.14°N, 45.63°W, 28 Jul 1993, E. Rald (ER 93.021, C-F-104319), 20 m, with Salix glauca in heathland. W-Greenland: Disko, Fortune Bay, 69.31°N, 53.88°W, 2 Aug 1986, T. Borgen (TB86.119, C-F-103566), 20 m. Qeqertarsuaq/Disko, Godhavn, 69.24°N, 53.54°W, 28 Jul 1986, T. Borgen (TB86.060, C-F-6922), 0 m. Disko, Qeqertarsuaq, 69.25°N, 53.55°W, 27 Jul 1986, T. Borgen (TB86.072, C-F-5090), 0 m. Kangerluarsunguaq/Kobbefjord, just south of the field station, 64.14°N, 51.39°W, 11 Aug 2009, T. Borgen (TB09K017, C-F-106753), 20 m, with Salix herbacea in snowbed. Kangerlussuaq, NE facing slopes along Lake Ferguson, 66.10°N, 50.61°W, 12 Aug 2016, H. Knudsen (HK16.082, C-F-104111), 300 m. Nuuk, airport area, 64.19°N, 51.67°W, 14 Aug 2008, T. Borgen (TB08.126, C-F-106749), 100 m, with Salix herbacea in snowbed. Sisimiut, from airport and round the mountain, 66.95°N, 53.72°W, 17 Aug 2016, H. Knudsen (HK16.181, C-F-108419), 30 m. Sisimiut, from airport and round the mountain, 66.95°N, 53.72°W, 17 Aug 2016, H. Knudsen (HK16.180, C-F-108418), 30 m. Sisimiut, into the E valley, 66.90°N, 52.86°W, 15 Aug 2016, H. Knudsen (HK16.134, C-F-104164), 0 m, with Salix herbacea and Salix arctica. Sisimiut, south of town, 66.93°N, 53.65°W, 18 Aug 2016, S.A. Elborne (SAE-2016.085-GR, C-F-106738), 20 m, with Salix herbacea in snowbed. N-Greenland: NE of Annekssø, 77.42°N, 21.33°W, 20 Jul 1990, B. Fredskild (BF 90 loc. 5, C-F-5113), 150 m. Stormlandet, N of Depotnæs, 77.6°N, 18.95°W, 20 Aug 1990, B. Fredskild (BF 90 loc. 8, C-F-5147), 20 m. Zackenberg, 74.5°N, 21°W, 14 Aug 2006, T. Borgen (TB06.170, C-F-119778) ,35 m, with Dryas sp. and Salix sp. in scrubland. Zackenberg, 74.5°N, 21°W, 5 Aug 2006, T. Borgen (TB06.090, C-F-119779), 30 m, with Dryas sp. and Salix arctica in grassland. Zackenberg, near Teltdammen, 74.5°N, 21°W, 5 Aug 2006, T. Borgen (TB06.090, C-F-119747), 30 m, with Dryas sp. and Salix arctica in scrubland. Zackenberg, shortly SW of Kamelen, 74.5°N, 21°W, 11 Aug 2006, T. Borgen (TB06.158, C-F-119775), 40 m, with Salix arctica and Bistorta vivipara in grassland. E-Greenland: Jameson Land, Constable Pynt, 70.75°N, 22.67°W, 30 Jul 1988, D. Boertmann (DB GR 88-40, C-F-3453), 2 m, with Salix arctica. Jameson Land, Constable Pynt, delta of Jyllandselv, 70.68°N, 24.08°W, 28 Jul 1988, D. Boertmann (DB GR 88-33, C-F-3448), 10 m, with Salix herbacea. Jameson Land, Nerlerit Inaat/Constable Pynt, delta of Gåseelv valley, 70.76°N, 22.65°W, 7 Aug 2017, H. Knudsen (HK17.149, C-F-105051), 40 m. Kuummiut, Torsukattak, 65.87°N, 37.01°W, 2 Aug 2008, T. Borgen (TB08.035, C-F-101622), 35 m.