Coniocarpon rubrocinctum (G. Merr. ex Grube & Lendemer) Perlmutter, R. Miranda & Bungartz, 2023

Perlmutter, Gary B., Miranda-González, Ricardo & Bungartz, Frank, 2023, Placement of Arthonia rubrocincta in Coniocarpon (lichenized Ascomycota: Arthoniaceae), with an extended range for the species in southeastern North America and the Caribbean, Phytotaxa 589 (3), pp. 278-282 : 279-280

Coniocarpon rubrocinctum (G. Merr. ex Grube & Lendemer) Perlmutter, R. Miranda & Bungartz comb. nov.

( Fig 1 )

MycoBank No. MB 847702

Basionym: — Arthonia rubrocincta G. Merr. ex Grube & Lendemer (2009: 9) .

Type : — UNITED STATES. Florida: Collier County, Fakahatchee Strand State Preserve , vicinity of Ranger Station , disturbed roadside vegetation and shaded swampy hardwood forest, on petioles of Sabal palmetto , 4 March 2009, J.C. Lendemer 15506 (holotype NY 01133735, n.v.; isotypes distributed as Lichens of Eastern North America Exsiccati #351, DUKE!).

Description: — Life form lichenized fungus. Thallus endoperidermal to epiperidermal, thin, effuse; surface whitish or greenish gray, in older specimens pale tan, smooth, occasionally with reddish or orange pigment crystals and areas of pinkish staining; prothallus brown, often as contact lines. Photobiont trentepohlioid alga, endoperidermal; cells (7.8–) 11.7 (–18.2) × (5.2–) 8.3 (–15.6) µm (n = 39), in short branched chains. Ascomata dispersed, sessile, elongate to furcate, lirellate with ±straight branches and acute tips, (0.4–) 1.0 (–1.6) × (0.2–) 0.3 (–0.5) mm (n = 60); disk flat, brown, often covered with whitish pruina; margin thick, coated with red or orange pruina.

In section ascoma (104–) 139 (–208) µm high (n = 6). Excipuloid layer lateral, (26–) 56 (–130) µm (n = 12) wide, dark brownish and infused with reddish pigment crystals. Epithecium (13–) 21 (–26) µm (n = 8) thick, brownish; hymenium hyaline, yellowish in thick sections, (52–) 64 (–91) µm high (n = 10); hypothecium pale brownish, (22–) 42 (–104) µm thick (n = 8). Asci abundant, clavate, (39.0–) 53.3 (–78.0) × (10.5–) 17.0 (–34.0) µm (n = 60), 8-spored, stipe short or indistinct, tholus (4.0–) 8.5 (–15.0) µm thick (n = 10); ascospores narrowly obovate, hyaline, smooth, faintly verrucose and appearing grayish and granular when postmature, macrocephalic, (4–)5-celled, (15.5–) 22.0 (–26.0) × (4.0–) 5.5 (–8.0) µm (n = 60). Pycnidia frequent, ±globose, partly immersed, (52–) 80 (–140) µm in diameter (n = 9), wall brown; conidia bacilliform, mostly straight, hyaline, (4–) 6.4 (–9) × ~1 µm (n = 10).

Chemistry: —Thallus UV–, K–, C–, KC–, PD+ golden yellow (psoromic acid); excipular pigment K+ magenta then fading; epithecium pigment dissolving in K. AMYLOIDITY: epithecium I+ blue, K/I+ dark blue; hymenium I+ blue or turning red, K/I+ dark blue or green in high concentrations; ascus protoplasm I–, K/I+ yellow-orange; ascus wall I–, K/I–. A hemiamyloid ring in the tholus of the asci not seen.

Substrate, ecology and distribution: —Found on woody palm frond bases in coastal, subtropical environments in southeastern North America (Florida to North Carolina) and the Caribbean ( Bahamas).

Additional specimens examined: — BAHAMAS. Cat Island. On leaf stem of thatch palm [ Coccothrinax argentata ], 9 July 1903, Anonymous s.n. (NCU) . UNITED STATES. Florida: Collier County, off James Scenic Drive 6.5 mi NNW of Ranger Station at Gate 12 along Tram Rd , 26°0.69’N, 81°24.35’W, on palmetto leaf sheath, 02 March 2009, M.P. Nelsen 4010 (F); Orange County , Sanford, on palmetto shafts, May 1908, S. Rapp 31 (FH) ; North Carolina: Brunswick County, Bald Head Island State Natural Area, behind East Beach in dune swale on palmetto frond base, 20 December 2022, G.B. Perlmutter 4307 (NCU) ; South Carolina: Horry County, North Myrtle Beach, Hilton Hotel , behind strand on base of palmetto frond, 18 October 2010, G.B. Perlmutter 182-a (NCU).

Figures

FIGURE 1. Coniocarpon rubrocinctum.A. Coastal habitat with phorophyte Sabal palmetto on right (Bald Head Island, North Carolina). B. Thallus from South Carolina showing prothallus, ascomata and pycnidia (Perlmutter 182a). C. Ascomatal section in water (Perlmutter 4307). D. Asci with spores in K/I (Anonymous s.n.). E. Ascospore in water (Perlmutter 4307). Scale bars: B = 2.0 mm; C = 50 μm; D = 20 μm; E = 10 μm.