Hebeloma ingratum Bruchet; Bull. mens. Soc. linn. Lyon 39: 125, 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 ingratum Bruchet; Bull. mens. Soc. linn. Lyon 39: 125, 1970. Fig. 29

Macroscopic description.

Cap 1.8-7.5 cm in diameter, convex to umbonate, margin often involute when young, sometimes serrate or crenulate, tacky when moist, occasionally hygrophanous, usually bicolored but sometimes unicolored, at center usually brown tones from ochraceous to cinnamon, at margin cream, occasionally 3-4 mm from margin a circle of water spots can be visible, without any traces of veil. Lamellae pale clay brown, adnate to emarginate, maximum depth 3-5 mm, number of lamellae {L} 50-80, droplets absent or visible with × 10 lens, occasionally with naked eye, white fimbriate edge usually present, sometimes very strongly. Stem 1.5-6.8 × 0.4-1.2 {median} × 0.5-1.3 {base} cm, stem Q (2.5-)4.4-11.1(-11.5), white lengthily fibrillose and white flocculose, most distinct in the upper half, cylindrical to clavate, occasionally subbulbous to bulbous. Context firm, interior stuffed, later hollow, rarely with superior wick, flesh not discoloring from base or sometimes weakly. Smell raphanoid. Taste raphanoid, usually mild, but sometimes bitter. Spore deposit dark olive buff to brownish olive to yellowish brown or umber.

Microscopic description.

Spores amygdaloid, sometimes limoniform, variably papillate from absent to very strongly, on ave. 10.0-11.0 × 5.5-6.5 µm, ave. Q = 1.7-1.9, yellow to yellow brown, usually guttulate, weakly to distinctly ornamented (O2O3), perispore somewhat to distinctly loosening ((P0) P1P2), indistinctly to weakly dextrinoid (D1D2). Basidia (20-)24-30(-33) × 6-10 µm, ave. Q = 3.2-3.9, mostly four-spored. Cheilocystidia clavate-lageniform, occasionally clavate-stipitate or ventricose, occasionally with characteristic apical or median wall thickening, sometimes geniculate or septate, on ave. 42-55 × 5-7 (apex) × 3.5-4.5 (middle) × 5-6.5 (base) µm, ratios A/M = 1.4-1.74, A/B = 0.9-1.28, B/M = 1.4-1.64. Epicutis and ixocutis, 75-300 µm thick (measured from exsiccata), maximum hyphae width 5-6.5 µm, sometimes encrusted, trama elements beneath subcutis oblong to sausage-shaped up to 15 µm wide. Caulocystidia up to 150 µm long, often cylindrical or slenderly clavate at the apex.

Collections examined.

S-Greenland: Paamiut, Taartoq/ Mørke Fiord, 62.01°N, 49.26°W, 4 Sep 1993, T. Borgen (TB93.205, C-F-103501), 20 m, with Betula glandulosa and Salix glauca in heathland. W-Greenland: Kangerlussuaq, fjord shore south of town, 66.98°N, 50.69°W, 26 Aug 2016, S.A. Elborne (SAE-2016.208-GR, C-F-106748), 20 m, with Salix glauca and Betula nana along streamside. Kangerlussuaq, Sandflugtsdalen, 67.02°N, 50.42°W, 21 Aug 1987, H. Knudsen (HK87.262, C-F-119732), 200 m, with Betula nana and Salix glauca . Sisimiut, 4 km E of the village, 66.94°N, 53.59°W, 18 Aug 2000, E. Ohenoja (EO18.8.00.36, OULU F050503), 70 m, in heathland.

Distribution.

Only known from two well-studied areas in low arctic southern and western Greenland, north to 67°. The general European distribution is in the Temperate zone, missing in southern Europe and with one record in the Hemiboreal zone in Finland. The Greenland records are the northernmost known and the first from North America and the first outside Europe.

Habitat and ecology.

Four collections from heath- and scrubland. Hosts are uncertain, both Betula nana and B. glandulosa as well as Salix glauca were present. No preference for a specific ecology. Beker et al. (2016) also list Betula and Salix , but also Fagus , Quercus and Populus as possible hosts.

Figures

Figure 29. Hebeloma ingratum A SAE- 2016.208, photograph S. A. Elborne B distribution of cited collections C spores x 1600 and D cheilocystidia x 1000 of SAE- 2016.208 in Melzer's reagent. Scale bars: 5 µm; microphotographs H. K. J. Beker.