Hydnum mulsicolor Liimat. & Niskanen, Mycologia 110: in press (2018)

Swenie, Rachel A., Baroni, Timothy J. & Matheny, P. Brandon, 2018, Six new species and reports of Hydnum (Cantharellales) from eastern North America, MycoKeys 42, pp. 35-72 : 35

Hydnum mulsicolor Liimat. & Niskanen, Mycologia 110: in press (2018) Figs 3H, 5J

Type.

SLOVENIA. Velike Lašče (45.8500; 14.6000): In forest of Picea abies , Fagus sylvatica , and Corylus avellana , GIS 1336 (holotype LJF1057).

Description.

Pileus 30-45 mm wide, round, convex when young, becoming plano-convex to funnel-shaped; surface dry, glabrous or matted-tomentose, bright orange to tan ("Zinc Orange" to “Ochraceous-Tawny”) becoming subzonate towards margin, sometimes distinctly umbilicate at center; margin incurved at first, becoming decurved, wavy, and lightening in color. Spines 1-7mm long, decurrent, pinkish cream with white tips. Stipe 25-45 × 5-8 mm, central or eccentric, equal or enlarging downwards, texture firm, smooth, with aborted spines at stipe apex and some texturing below, cream white, sometimes with small white cottony patches, staining orange when handled, a dense mat of basal mycelium present at base. Context not observed. Odor mild or pleasant. Taste not distinctive.

Basidiospores 6.5 –7.7– 8.5 μm × (5.5)6 –7.1– 8.5 μm, Q=1.00 –1.08– 1.19(1.24) (n=46/3), subglobose, smooth, hyaline in KOH. Basidia 52-60 × 7.5-9.5 μm with 3-4(5) sterigmata. Pileipellis an interwoven cutis, hyphae smooth, cylindrical, thin-walled, mostly 4-6 μm wide. Clamp connections present.

Distribution.

Eastern U.S. and Central Europe - Ohio, Virginia, North Carolina, Tennessee (GenBank AJ547885, AJ547868, AJ783969), and Slovenia (type), Switzerland (GenBank KU612545, KX086216).

Ecology.

In deciduous or mixed forests with Quercus . July to September.

Other specimens examined.

UNITED STATES. North Carolina: Blue Ridge Parkway near Little Switzerland, deciduous woodlot with Quercus , 1100 m, 19 Aug 2016, M. Hopping RAS105 (TENN 073015). Blue Ridge Parkway near Little Switzerland, in mixed woods, 1100 m, 19 Aug 2016, D. Boes RAS108 (TENN 073018). Buncombe County, Tanbark Ridge, growing singly in mature acidic cove forest with Quercus and Acer , 915 m, 4 Sep 2016, M. Hopping MH16006 (TENN 073550). Tennessee: Great Smoky Mountains National Park, Cherokee Orchard, Bullhead Trail, on soil in mixed forest, 1340 m, 16 Jul 2015, R.A. Swenie RAS023 (TENN 070321). Virginia: Shenandoah National Park, milepost 21, 1000 m, 9 Sep 2016, RAS120 (TENN 073023).

Discussion.

Hydnum mulsicolor is the only species of Hydnum in eastern North America that is also known to occur in Europe based on ITS phylogenetic analysis. The basidiomes are small to medium-sized with strongly decurrent spines, and the pileus color ranges from strikingly orange to tan. Prominent basal mycelium is also present as a dense mat or as distinct rhizomorphs at the stipe base. In the eastern US, H. mulsicolor is often found with Quercus in mixed or hardwood forests. It is closely related to H. submulsicolor and H. canadense , both of which are known only from coniferous forests in eastern North America and have slightly larger spores than H. mulsicolor ( Niskanen et al. 2018).