Gyroporus borealis Davoodian, O. Asher, Sturgeon, Ammirati & Delaney, 2020

Davoodian, Naveed, Hosaka, Kentaro, Raspé, Olivier, Asher, Olivia A., Franck, Alan R., Kesel, André De, Delaney, Terrence P., Ammirati, Joseph F., Nagasawa, Eiji, Buyck, Bart & Halling, Roy E., 2020, Diversity of Gyroporus (Gyroporaceae, Boletales): rpb 2 phylogeny and three new species, Phytotaxa 434 (3), pp. 208-218 : 214-216

Gyroporus borealis Davoodian, O. Asher, Sturgeon, Ammirati & Delaney , sp. nov. ( Fig. 3 )

Type:— UNITED STATES. Vermont: Chittenden Co., South Burlington, East Woods, 11 Oct 2012, T.P. Delaney s.n. (holotype NY! [NY1393558]).

Etymology: The specific epithet means “northern” (from Latin, ultimately derived from Greek), referring to the native occurrence of this species in the northeastern United States.

MycoBank: MB831759

Pileus 3.5–6.5 cm, convex to plane to slightly concave, very fine matted to smooth-subvelvety to patchily furfuraceous, orange-brown, cinnamon brown to sometimes reddish (especially in dried condition) 6D-E6,5 ( Kornerup & Wanscher 1978). Flesh white, unchanging. Tubes adnexed to subadnate, pale yellow to dirty yellow, occasionally with an orangish hue when dried. Stipe 4–5 cm long, 1–1.6 cm broad, slightly curved, bumpy, subconcolorous to concolorous with pileus, pale reddish-brown to concolorous with pileus in dried condition, pubescent, pithy/chambered.

Spores (8.0–)8.8–11(–12) × 4.8–5.6(–6.4) μm (Q m =1.9), smooth, yellow-hyaline, ellipsoid, sometimes subreniform to ovoid. Basidia 23.2–30.4 × 11.2–13.6 μm, clavate, with pronounced sterigmata. Cheilocystidia 31.2–36.8 × 6.4–8 μm, ventricose to ventricose-rostrate. Pleurocystidia none found, apparently absent or rare. Basidioles 16.8–24 × 8–12 μm, subclavate. Pileipellis a trichodermium of erect, tangled elements (8–10 µm broad) with rounded, tapered, or cystidioid end cells (10–14 µm broad); elements submelleous in aggregate. Clamp connections present in pileipellis.

Ecology and distribution: Recorded with native vegetation in Vermont ( Betula , Tsuga ; Acer in vicinity) and Ohio ( Quercus , Fagus , Tsuga ; mixed hardwoods in vicinity), USA. Recorded under planted landscape trees in Washington, USA.

Additional material examined: UNITED STATES. Ohio: Columbiana Co., Calcutta-Smith Ferry Road, 31 Aug 2015, W.E. Sturgeon s.n. (NY2072723). 9 Sep 2015, W.E. Sturgeon s.n. (NY2072724). Washington: King Co., University of Washington, 29 Jun 2011, J.F. Ammirati 13725 (WTU-F-48413).

Commentary: G. borealis is characterized by an orange-brown pileus that is furfuraceous to subvelvety; the stipe is generally subconcolorous with the pileus. This northeastern North American species apparently also occurs in northwestern North America (where Gyroporus is rare and presumably not native) by way of ectomycorrhizal planted landscape trees (e.g. Betula , Quercus , Pinus , etc.), thus indicating that some species of Gyroporus can be moved geographically based on human activities. G. borealis is a segregate species of G. castaneus s.l. as outlined in Davoodian et al. (2018). An rpb 2 sequence from GenBank (FJ536636) nests close to G. borealis , however, since the physical specimen is unknown to the authors it is not treated here. In comparison to G. smithii (described below), also a North American species, G. borealis has larger and more elongated spores and displays more brown and red tones in the pileus and stipe surfaces.

Figures

FIGURE 3. Gyroporus borealis sp. nov. Specimen NY1393558 (holotype). Top: hymenophore view. Bottom: pileus view. Images: Terrence Delaney.