Gliophorus subaromaticus Rockefeller, G. W. Griff. & D. J. Harries 2026, comb. nov.

Gliophorus subaromaticus (A. H. Sm. & Hesler) Rockefeller, G. W. Griff. & D. J. Harries comb. nov. Fig. 9 Gliophorus subaromaticus (A. H. Sm. & Hesler) Rockefeller, G. W. Griff. & D. J. Harries, comb. nov. Hygrophorus unguinosus var. subaromaticus A. H. Sm. & Hesler, Lloydia 5 (1): 81 (1942). Basionym. Hygrophorus subaromaticus (A. H. Sm. & Hesler) Largent, The Agaricales (Gilled Fungi) of California, 5. Hygrophoraceae (California): 106 (1985). Synonym. Holotypus. USA • California, Orick, Prairie Creek State Park, Nov 28 1937, (voucher MICH: 10963 [Smith 9167]). Augmented here with ITS sequence (PX 746788) of holotype: UNITE / PlutoF: SH 0910861.10 FU (1.5 % threshold). Description. Pileus 10–50 mm broad, convex to broadly convex with incurved margin, becoming plane or nearly so, sometimes with a low flattened umbo, colour “ buffy-brown ” on the disc, “ pale olive-buff ” near the whitish margin (a dull olive greyish-brown to pallid) in the type, pale Buff with or without a white margin in iNaturalist: 256214946 (ITS: PV 791511), white with pale Buff disc in iNaturalist: 191417805 (ITS: PP 975575) and pure white in both iNaturalist: 9640562 (ITS: MG 926555) and iNaturalist: 148999043 (ITS: OR 593569), glabrous slimy-viscid, margin striatulate in the type, but not in the recent collections. Context thin, very soft and fragile, whitish. Stipe 5–6 cm long, 6–10 mm thick concolorous with gills when fresh, but drying pale grey like the pileus in type, equal, hollow, fragile, slimy viscid, as in G. laetus, glabrous. Lamellae bluntly adnate with decurrent tooth in type or sinuate, white, with a faint grey cast in type, broad sub-distant, edges even; 1–2 lengths lamellulae inserted. Taste and odour faint, but disagreeable subaromatic in type, taste mild or slightly disagreeable, indistinct, similar to burnt plastic. Lamellae white (not fluorescing blue) under UVf 365 nm. Basidiospores 8.1–10.2 × 5.6–6.1 µm in type description, pale yellow in Melzer’s reagent. Cuticle a thick (180–300 µm), gelatinous zone, the hyphae narrow colourless, more or less interwoven (an ixotrichodermium). Hypodermium a rather well-defined brownish zone. Pileus trama of radial hyphae. Clamp connections absent or very rare. Habitat. On soil under coastal redwoods (Sequoia sempervirens). Geographical distribution. Known only from coastal redwood forests in north-western North America (Fig. 5 B). Additional specimens examined. USA • California: (1) Mendocino Co., Jackson State Forest, (39.3890, -123.68460, 26 Jan 2018, A. Rockefeller [voucher AR-2018 a]), iNaturalist: 9640562 (ITS: MG 926555); (2) Humboldt Co., Eureka Area, Arcata Community Forest, near Sequoia sempervirens (40.88326, -124.06329, 16 Feb 2023, Mandy Hackney [voucher HAY-F-000661]), iNaturalist: 148999043 (ITS: OR 593569); (3) Humboldt Co., Eureka Area, McKay Community Forest, near Sequoia sempervirens (40.7501, -124.1446, 18 Nov 2023, Dean Lyons [voucher HAY-F-002303]), iNaturalist: 191417805 (ITS: PP 975575). Notes. This species, known only from the coastal regions of north California in North America, is found in coastal redwood (Sequoia sempervirens) forest. Its key distinguishing feature is its unpleasant odour, but the odour is not always present. The lamellae appear white under UVf 365 nm, distinguishing it from the bright blue fluorescence of lamellae in G. calunus. Though first recorded in 1937, most records date from 2013 or later. Reports of this species from Vancouver B. C. in Canada are a misapplied name. M. Berbee & F. Stonehouse at UBC obtained an ITS sequence of a collection by A. and U. Češka from Vancouver (UBC-F-3506) that most closely matched the type description of H. subaromaticus. The GenBank BLAST of that sequence confirmed that it had been misidentified as H. subaromaticus and instead belonged to a possibly unknown species, near Cuphophyllus sp. ‘ PNW 01 ’ and C. subaustraligus. Although an ixocutis was found on the pileus and stipe of the Vancouver collections, the specimens differed in having only a somewhat viscid rather than glutinous pileus that is typical of both G. calunus and H. subaromaticus.