Albomagister subaustralis (A.H. Sm. & Hesler) Sánchez-García, Birkebak & Matheny

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 : 362

Albomagister subaustralis (A.H. Sm. & Hesler) Sánchez-García, Birkebak & Matheny , Taxon 63: 1000 (2014) Figs. 5A–5B , 7A– 7C .

= Hygrophorus subaustralis A.H. Sm. & Hesler , Lloydia 5: 46 (1942)

Habit tricholomatoid, resembling small forms of Tricholoma columbetta . Pileus 27–44 mm wide, bluntly conical with an inflexed margin when young, expanding to plano-convex or applanate with age, with a broad umbo; surface dull, matte, felted and slightly radially fibrillose towards the margin; white, at times yellowish at the center, not hygrophanous; context white and dull, odor mild or somewhat unpleasant, not farinaceous. Lamellae sinuate, close with several tiers of lamellulae, slightly yellowish white, broad (up to 7 mm deep), edges concolorous and entire in appearance. Stipe 45–55 × 5–10 mm, equal, at times somewhat flexuous, fragile; surface dry but on occasion with beads of moisture at the apex, tomentose on the lower part, veil absent; white; stuffed to hollow. Basidiospores 4– 4.6 – 5(5.3) × 3.5– 3.8 –4(4.3) µm, Q 1.10– 1.25 –1.40 (n = 61/3), broadly elliptic to subglobose, at times with a guttule, hyaline, thin-walled, inamyloid and nondextrinoid, with a distinct apiculus, white in deposit. Basidia 20–28 × 5–6 µm, 4-spored, narrowly clavate to cylindric, hyaline, thin-walled. Pleurocystidia 26–56 × 8–15 µm, narrowly utriform or fusiform to utriform, rarely oblong to obovate, with rounded or obtuse apices, long pedicellate, thin-walled, hyaline; scattered, somewhat more frequent towards the fertile lamellar edges. Cheilocystidia similar to pleurocystidia, at times slenderly clavate, scattered and mixed with fertile basidia. Pileipellis a cutis giving rise to upright and constricted to flexuous cylindric hyphae, 3–9 µm wide, thin-walled, hyaline. Stipitipellis without caulocystidia, hyphae of stipe surface 3– 5 µm wide, hyphae appressed or somewhat recurved, smooth, thin-walled, hyaline. Clamp connections present in all tissues.

TAXONOMIC NOTES: Albomagister subaustralis is the most commonly collected species of Albomagister in the southern Appalachians. It also produces the largest basidiomes among the white-colored species. Albomagister luteifolius is similar but is characterized by the smaller Inocybe geophylla- like basidiomes. Albomagister leucoloma differs from A. subaustralis by the pileus with grayish drab tints and unique phylogenetic position.

DISTRIBUTION AND ECOLOGY: Albomagister subaustralis is known only from the southern Appalachians (Georgia, North Carolina, South Carolina, Tennessee) in rich and poor (acidic) cove hardwood forests (<1000 m elev) mixed with hemlock and/or pine and also in oak-hickory-beech forests on karst topography. Potential ectomycorrhizal trees include Tsuga , Betula , Carpinus , Carya , Fagus , Quercus , Pinus , and Tilia . Reports from outside the southern Appalachians have not been confirmed with molecular annotations. Most basidiomes were observed from August to October.

ADDITIONAL SPECIMENS EXAMINED: USA, North Carolina, Swain County, Great Smoky Mountains National Park ( GSMNP), Indian Creek , 23 August 1942, L. R. Hesler & A. J. Sharp LRH14423 (TENN-F-014423); ibid., 12 September 1947, L. R. Hesler LRH17951 (TENN-F-017951); ibid., L. R. Hesler & A. J. Sharp LRH18628 (TENN-F-018628); ibid., 14 August 1952, L. R. Hesler LRH020463 (TENN-F-020463); Martins Gap , GSMNP, beside the trail, 2 September 1938, A. H. Smith AHS10844 (holotype, MICH 10951 ); South Carolina, Oconee County, Oconee State Park, Mountain Rest , 22 September 2013, J. M. Birkebak JMB092213-01 (TENN-F-070997); Tennessee, Blount County, GSMNP, Cades Cove , 25 September 1957, L. R. Hesler LRH22663 (TENN-F-022663); ibid., 26 August 1958, L. R. Hesler LRH023195 (TENN-F-023195); ibid., campground area of Cades Cove , 6 August 1959, L. R. Hesler LRH23221 (TENN-F-023221); ibid., 26 September 1973, L. R. Hesler LRH39069 (TENN-F-039069); Cocke County, GSMNP, Maddron Bald Trail , 4 August 2012, S. A. Trudell SAT-12–217-02 (TENN-F-067343); Monroe County, Tellico Plains , Bald River Falls , Cherokee National Forest , 1 October 2011, W. Burnette WBU11 (TENN-F-066902); Sevier County, GSMNP, Elkmont area, Jakes Creek Trail , 4 August 2009, M. G. Wood MGW676 (TENN-F-064620); ibid., E. C. Vellinga ECV4049 (TENN-F-064621); Sevier County, GSMNP, Greenbrier area at intersection of Greenbrier Road and Ramsey Prong Road, Cemetery Trail, 2 September 2013, M. G. Wood MGW1296 (TENN-F-068710).

Figures

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.

Fig. 7. Salient microscopic features for Albomagister subaustralis (MGW676). (A) Basidiospores. (B) Pleurocystidia. (C) Cheilocystidia. Horizontal bar = 10 µm for basidiospores; vertical bar = 25 µm for cystidia. Line art by M.G. Grady.