Hebeloma marginatulum (J. Favre) Bruchet; Bull. mens. Soc. linn. Lyon 39(6(Suppl.)): 43, 1970.

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 marginatulum (J. Favre) Bruchet; Bull. mens. Soc. linn. Lyon 39(6(Suppl.)): 43, 1970. Fig. 15

Macroscopic description.

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.

Microscopic description.

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 (D0D1). 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.

Collections examined.

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.

Distribution.

Hebeloma marginatulum is widespread and, apparently, one of the most common Hebeloma species in Greenland (11.1% of the collections, see Table 3 ), also common in other parts of North America and present in parts of Europe ( Beker et al. 2016; Cripps et al. 2019). It is a truly arctic-alpine species hardly found outside these areas. Arctic-alpine.

Habitat and ecology.

Forty-five collections with many hosts. Twenty collections with Salix ( S. herbacea 9, S. glauca 6, S. arctophila 3 and S. arctica 2), two with Betula pubescens var. pumila , two with Betula sp. and three with Dryas octopetala and D. integrifolia (as always, other potential hosts may have been nearby). In the Rocky Mountains, it is also common, found with Salix arctica , S. reticulata and S. planifolia ( Cripps et al. 2019). Beker et al. (2016) have S. herbacea and S. polaris as the main hosts. Hebeloma marginatulum occurs on a variety of soil types seemingly without specific preferences.

Figures

Figure 15. Hebeloma marginatulum A HK 16.082, photograph H. Knudsen B distribution of cited collections C spores x 1600 and D cheilocystidia x 1000 of HK 16.082 in Melzer's reagent. Scale bars: 5 µm; microphotographs H. K. J. Beker.