Hebeloma colvinii (Peck) Sacc.; Syll. fung. (Abellini) 5: 805, 1887.

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 colvinii (Peck) Sacc.; Syll. fung. (Abellini) 5: 805, 1887. Fig. 9

Macroscopic description.

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.

Microscopic description.

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 (O1O2), perispore not noticeably loosening (P0), indistinctly dextrinoid (D0D1), 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.

Collections examined.

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.

Distribution.

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.

Habitat and ecology.

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.

Note.

Hebeloma colvinii was originally described as " Agaricus Hebeloma 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).

Figures

Figure 9. Hebeloma colvinii A HK 16.005, photograph H. Knudsen B distribution of cited collections; C spores x 1600 and D cheilocystidia x 1000 of HK 16.005 in Melzer's reagent. Scale bars: 5 µm; microphotographs H. K. J. Beker.