Polymeridium stromatocorticatum B.Barbosa, Aptroot, L.A.Santos & M.Cáceres, 2024

C, Bruno Micael, Barbosa, ardoso, A, Lidiane, Santos, lves dos, Oliveira, Isaías de, Junior, Oliveira, Dayane de, Lima, Aptroot, André, E, Marcela, S, ugenia da & Cáceres, ilva, 2024, New records of Polymeridium (Müll. Arg.) R. C. Harris from Brazil with description of a new species from the Caatinga, and a checklist of the Brazilian species, Cryptogamie, Mycologie 20 (4), pp. 39-46 : 41

Polymeridium stromatocorticatum B.Barbosa, Aptroot, L.A.Santos & M.Cáceres , sp. nov.

( Fig. 1 )

Polymeridium differing from all known species in the genus by a corticate thallus and aggregated ascomata; ascospores 3-septate, 23-26 × 5.5-6.5 µm.

TYPE MATERIAL. — Brazil • Bahia, Raso de Catarina ; on tree bark; 10.X.2021; leg. L.A. Santos; holotype: ISE [ ISE 54094 ]; isotype: ABL .

ETYMOLOGY. — Named after the stromatic ascomata and the corticate thallus, both unique characters within the genus.

MYCOBANK. — MB852549.

DESCRIPTION

Thallus crustose, up to 3 cm diam., corticate, ochraceous, surrounded by a 0.2 mm wide brown prothallus line. Ascomata closed, 0.3-0.4 mm diam., aggregated in groups of 2-10, black, fused with walls sideways, without crystals; walls c. 30 µm thick. Ostioles apical, with a whitish grey pruina. Hamathecium not inspersed. Ascospores 8/ascus, 3-septate, hyaline, 23-26×5.5-6.5 µm, lumina rectangular; surrounded by a c. 1 µm thick gelatinous sheath.

This species is characterized by the combination of a corticate thallus and aggregated ascomata, while the ascospores display the typical features of a Polymeridium .

Chemistry: thallus KOH-negative, UV-negative; no substances found.

CHECKLIST OF POlYMeRidiUM SPECIES FROM BRAZIL

Figures

FIG. 1. — Polymeridium stromatocorticatum B.Barbosa, Aptroot, L.A.Santos & M.Cáceres, sp. nov.: A, B, ascospores and habitus of holotype. Scale bars: 2 µm.