Four new species of Albomagister (Agaricales) from eastern North America Matheny, P. Brandon Lebeuf, Renée Sánchez-García, Marisol Graddy, Mary G. Trudell, Steven A. Wood, Michal G. Vellinga, Else C. Botany 2024 2024-09-01 102 9 355 365 Lebeuf, Matheny & Vellinga Lebeuf, Matheny & Vellinga 2024 [862,1527,1881,1904] Agaricomycetes Tricholomataceae Albomagister Fungi Agaricales 2 357 Basidiomycota species griseosquamosus sp. nov.  MYCOBANK: MB851399.   TYPE:  USA, Tennessee, Sevier County, Great Smoky Mountains National Park, Elmont, Jakes Creek Trail( 35.6764 -83.3971), in humus in acidic cove hardwood forest under various hardwoods and  Tsuga canadensis,  4 August 2009,  J. Lennie ECV4038( holotypedesignated here, TENN-F-064609).  DIAGNOSIS: Differs from the white species of  Albomagisterby the gray squarrose to appressed-scaly pileus and stipe.   Habittricholomatoid. Pileus 25–50 mmwide, campanulate to plano-convex and at times with a low broad umbo, more flattened with age; margin decurved, occasionally torn or undulating; surface dry, initially with a whitish ground color, becoming gray and completely covered with dense small dark gray to blackish squamules, these squarrulose when young and more like fibrillose-scales in more-or-less concentric bands in age, not hygrophanous; context pale gray with dark gray areas, odor, and taste indistinct, absent, or mild. Lamellaesinuate to adnate, close to crowded with ca. 55–60 L and 1–3 tiers of lamellulae, thick, narrow ( 3–5 mm), white to pale gray or gray with white edges that darken to gray, edges sometimes eroded. Stipe35–70 × 4–7 mm, equal to slightly narrowed or slightly enlarged at the base; surface dry, veil absent, fibrillose at the apex but mostly with gray scaber-like squamules or with the squamules covering the entire length on a whitish or paler background, squamules smaller towards the base, becoming lacerate-scaly with age; context pale gray, becoming paler towards the nearly white base; hollow. Basidiospores6– 7.1–8 × (4)4.5– 5.6–6.7 µm, Q 1.10– 1.28–1.57 ( n= 65/4), smooth, elliptic to broadly so or subglobose, with a guttule, hyaline, inamyloid, with a distinct apiculus, white in deposit. Basidia25– 37 × 7–9.5 µm, 4-spored, clavate to subcylindric, hyaline. Pleurocystidia38–74 × 11–20 µm, obovate, sphaeropedunculate, broadly clavate, or fusiform-rostrate, with a long pedicel, with a rounded or mucronate apex, with thin or slightly thickened wall, brown pigmented. Cheilocystidiaforming a sterile lamellar edge, 24–80 × 7–15 µm, often narrowly lageniform to abruptly fusiform, very long pedicellate, walls slightly thickened and brown pigmented. Pileipellisan irregular trichoderm with chained elements, these narrowed gradually, hyphae incrusted; terminal cells 45–115 × 9–18 µm, utriform to somewhat conical, less often narrowly lageniform, base generally broad, apices often with a moniliform excrescence, at times rostrate, brownish pigmented. Stipitipellissimilar to pileipellis. Clamp connectionspresent, large, and conspicuous.  TAXONOMIC NOTES:  Albomagister griseosquamosuswas previously reported as “undet gray scaly” in Sánchez-García et al. (2014, 2017). This species resembles  Tricholoma squarrulosumBres.and  T. atrosquamosumSacc., but in its outward appearance  A. griseosquamosusdiffers from these by the more elongated non-bulbous stipe and non-farinaceous odor and taste. Microscopically,  A. griseosquamosusdiffers readily from these by the presence of distinct pleuro- and cheilocystidia and the large conspicuous clamp connections found throughout the all tissues.   Fig. 4.Basidiomes of  Albomagister luteifolius. (A) HRL2773(holotype, DAOM 984969). (B) HRL3286(DAOM 984970). Bars = 1 cm. Photos by R. Lebeuf.   Fig. 5.Basidiomes  Albomagister subaustralis. (A) MGW1296(TENN-F-068710). (B) SAT-12–217-02(TENN-F-067343). Bars = 1 cm. Photo A by M.G. Wood; photo B by S.A. Trudell.  Thebasidiospores of the Quebeccollections (6– 6.5–7.5 × 4– 4.8–5) µm, Q 1.09–  1.30–1.63 are somewhat smaller than the typeand ECV5690from Tennessee. Althoughnot analyzed here, an rpb1sequence was also produced from the typeof  A. griseosquamosus—— KU139073( Sánchez-García and Matheny 2017).  ETYMOLOGY:  griseosquamosus(Latin), gray scaly, in reference to the gray scales on the pileus and stipe  DISTRIBUTION AND ECOLOGY:  Albomagister griseosquamosusapparently is widely distributed in eastern North America, having been found in both Quebecand Tennessee, although there is a broad sampling gap between these regions. It occurs on acidic soils (where known) at relatively low elevations (< 600 m), in mixed and cove hardwood forests containing some mixture of the following ectomycorrhizal trees:  Abies,  Fagus,  Betula,  Tsugaand/or  Tilia. Basidiomes have been observed August to September.   OTHER SPECIMENS EXAMINED: Canada, Quebec, Saint-Stanislas, Parc de la rivière Batiscan, secteur Murphy, trial Le Buis( 46.5891 -72.4125), solitary on ground in leaf litter in mixed forest under  Abies balsamea,  Betula alleghaniensis, 7 September 2020, R. Lebeuf & A. Paul HRL3282(DAOM 984972); Saint-Alexis-des-Monts, chemin Yvon-Plante ( 46.5099 -73.1955), gregarious on soil in northern hardwood forest under  Fagus grandifolia,  Abies balsamea,  Acer, 16 Aug. 2023, R. Lebeuf & A. Paul HRL4268(R.L. pers. fung., iNat178773906). USA, Tennessee, Sevier Co., Great Smoky Mountains National Park, Greenbrier, Ramsey Cascades Trail ( 35.7028 -83.3575), acidic cove hardwood forest including  Tsuga canadensis,  Betula alleghaniensis,  Tilia americana,  Quercus, 5 September 2013, E. C. VellingaECV5690 (TENN-F-068763). 5209581303 in humus in acidic cove hardwood forest under various hardwoods and Tsuga canadensis 2009-08-04 J. Lennie United States of America Sevier County 35.6764 Great Smoky Mountains National Park, Elmont, Jakes Creek Trail 6 -83.3971 3 358 TENN-F-064609 1 Tennessee holotype