Albomagister luteifolius Lebeuf, Matheny & Sánchez-García, 2024

Matheny, P. Brandon, Lebeuf, Renée, Sánchez-García, Marisol, Graddy, Mary G., Trudell, Steven A., Wood, Michal G. & Vellinga, Else C., 2024, Four new species of Albomagister (Agaricales) from eastern North America, Botany 102 (9), pp. 355-365 : 360-361

Albomagister luteifolius Lebeuf, Matheny & Sánchez-García , sp. nov. ( Figs. 4A–4B , 6G–6I )

MYCOBANK: MB851401.

TYPE: Canada, Quebec, Saint-Thuribe, Rang Saint-Léon (42.3327 -72.9571), on soil in mixed forest including Fagus grandifolia with few Abies balsamea , 16 September 2018, R. Lebeuf HRL2773 (holotype designated here DAOM 984969 , isotype TENN-F-074689 ) .

DIAGNOSIS: Differs from other species of Albomagister by the habit similar to Inocybe geophylla , yellowing lamellae, and distinct phylogenetic position sister to A. subaustralis .

Habit inocyboid resembling Inocybe geophylla in outward appearance. Pileus 7–30 mm wide, campanulate, margin inflexed then deflexed; surface dry, with appressed radial fibrils, at times with watery drops near the margin; white, pale yellow over the center; context yellowish white to pale yellow (3A2, 3A3), thin; odor none, taste bitter. Lamellae adnexed to sinuate, distant to moderately so, 1.5–5 mm deep; white at first, becoming yellowish white (4A2) and darker yellow with age, light yellow (near 4A5) after drying, not waxy. Stipe 20–60 × 1–6 mm, equal, often curved; surface dry, veil not observed, pruinose to flocculose at the apex, fibrillosestriate below, when young with watery drops near the apex; white; context yellowish white to pale yellow. KOH negative on surfaces of the pileus and stipe and on the stipe context. Basidiospores 4.5– 5.0 –6 × (3–)3.5– 3.7 –4(–4.5) µm, Q 1.13– 1.37 –1.57(–1.71) (n = 90/3), elliptic to broadly elliptic (more broadly so from less mature basidiomes), smooth, inamyloid, white in deposit. Basidia 21–27 × 6–7 µm, 4-spored, clavate. Pleurocystidia 38–66 × 8–14 µm, frequent, fusiform to subutriform or subcylindric or oblong, often shortpedicellate, thin-walled, hyaline. Cheilocystidia 48–75 × 8– 14 µm, similar to pleurocystidia but at times long-pedicellate (pedicels up to 20 µm long). Pileipellis a cutis composed of cylindric hyphae 2–7 µm wide; tramal hyphae inflated, 5–20 µm wide. Stipitipellis without caulocystidia; hyphae cylindric, 3–9 µm wide. Clamp connections abundant in all tissues.

TAXONOMIC NOTES: Albomagister luteifolius and A. subaustralis are difficult to distinguish based on morphology only. Indeed, both are sister taxa, but A. luteifolius , based on the proportion of samples sequenced, appears to be the less frequently encountered of the two species. Based on available data, A. luteifolius is best distinguished from A. subaustralis by the smaller Inocybe geophylla- like habit. Comparison of dried materials of both species suggests neither can be reliably distinguished by the yellowish to ocher-yellow color of the dried lamellae. Albomagister luteifolius does not appear to be common but has been overlooked and misidentified as A. subaustralis in the past (see AHS14872 cited under H. subaustralis in Hesler and Smith 1963). The species occurs in mixed hardwood forests and mixed forests including conifers and has a wide geographic range having been confirmed by molecular data from Quebec and the southern Appalachians during August and September. Albomagister luteifolius equates to Albomagister sp. 2 in Sánchez-García et al. (2014, 2017).

ETYMOLOGY: luteifolius (Latin) , yellow gills, in reference to the yellowish-tinged lamellae.

DISTRIBUTION AND ECOLOGY: Albomagister luteifolius is widely distributed across eastern North America, having been found in Quebec, North Carolina, and Tennessee, but a broad sampling gap occurs between those regions. It occurs singly to scattered or gregarious on acidic or possibly more nutrient enriched soils at relatively low- to mid-elevations (<1200 m) in leaf litter in mixed hardwood- Tsuga canadensis dominated forests, cove hardwood forests under Quercus , northern hardwood forests, and in mixed forests containing Fagus , Abies , and/or Betula . Basidiomes were recorded in August and September.

Sánchez-García and Matheny (2017) also produced an rpb1 sequence ( KU139018 ) for MSG137 (TENN-F-068776).

OTHER SPECIMENS EXAMINED: Canada, Quebec, Saint-Thuribe, Rang Saint-Léon (42.3327 -72.0571), in beech-maple forest under Fagus grandifolia , 11 September 2020, R. Lebeuf & A. Paul HRL3286 (DAOM 984970); ibid., under Fagus grandifolia , Betula alleghaniensis , 11 September 2020, R. Lebeuf & A. Paul HRL3287 (DAOM 984971). USA, North Carolina, McDowell Co., Marion, Armstrong Creek (35.6830 -82.0058), in mixed hardwood forest with Tsuga canadensis , 21 September 2012, M. Sánchez-García MSG136 (TENN-F-068775); McDowell Co., Little Switzerland, Blue Ridge Parkway, Swofford Road near Table Rock Overlook (36.5186 -80.9358), in mixed hardwood forest along a gravel road, 21 September 2012, B.P. Looney MSG137 (TENN-F-068776); McDowell Co., near Marion, Pisgah National Forest, Victor Road (35.803 -82.162), in a swamp forest bog complex under Betula , Tsuga , Quercus , 22 September 2023, S.R. Warwick & P.B. Matheny PBM4797 (TENN-F-078516); Mitchell Co., Roses Creek, on acidic soil in cove hardwood forest, 22 September 2023, C.R. Noffsinger CRN92223A (TENN-F-078620). Tennessee, Blount Co., Great Smoky Mountains National Park, Cades Cove (35.5942 -83.842), in rich cove hardwood forest with Quercus , 17 Aug. 1939, A.H. Smith AHS14872 (MICH 58090 as “ Hygrophorus subaustralis ”).

Figures

Fig. 4. Basidiomes of Albomagister luteifolius. (A) HRL2773 (holotype, DAOM 984969). (B) HRL3286 (DAOM 984970). Bars = 1 cm. Photos by R. Lebeuf.

Fig. 6. Salient microscopic features of the new species of Albomagister. Albomagister griseosquamosus (ECV4038, holotype): (A) Basidiospores. (B) Pleurocystidia. (C) Cheilocystidia. Albomagister leucoloma (ECV4202, holotype): (D) Basidiospores. (E) Pleurocystidia. (F) Cheilocystidia. Albomagister luteifolius (HRL2773, holotype): (G) Basidiospores. (H) Pleurocysidia. (I) Cheilocystidia. Albomagister parviniveus (MSG144, holotpe). (J) Basidiospores. (K) Cheilocystidia. Horizontal bars = 10 µm for basidiospores; vertical bars = 25 µm for cystidia.