Ocellularia thailandica Naksuwankul, Kraichak & Lumbsch

Naksuwankul, Khwanyuruan, Kraichak, Ekaphan, Parnmen, Sittiporn, Luecking, Robert & Lumbsch, H. Thorsten, 2016, Five new species of Graphidaceae (Ascomycota, Ostropales) from Thailand, MycoKeys 17, pp. 47-63 : 55

Ocellularia thailandica Naksuwankul, Kraichak & Lumbsch sp. nov. Figure 4 F–H

Type.

THAILAND, Ubon Ratchathani Province, Pha Tam National Park, trail to Huai Sanom, 15°27'N, 105°34'E, 245 m, dry evergreen forest, on bark; 12 April 2013, K. Papong 8458 (holotype: MSUT; isotype: F).

Diagnosis.

Differing from the similar Ocellularia viridipallens in having broader ascospores with up to 7 septa.

Etymology.

The specific epithet refers to the country where the type specimen was collected.

Description.

Thallus corticolous, epiperidermal, up to c. 5 cm diam., continuous; surface uneven-verrucose to rimose, light yellowish green, medulla white; prothallus absent. Thallus in section 40-60 µm thick, with prosoplectenchymatous cortex, 5-7 µm thick, photobiont layer 15-25 µm thick, and medulla 20-30 µm thick, with scattered clusters of calcium oxalate crystals. Photobiont Trentepohlia ; cells rounded to irregular in outline, in irregular groups, green, 7-8 × 5-9 µm. Ascomata rounded, erumpent, with complete thalline margin, 0.3-0.5 mm diam., 0.12-0.2 mm high; disc covered by 0.05-0.1 mm wide pore; proper margin indistinct, entire to slightly fissured, visible as whitish rim around the pore; thalline margin entire to slightly fissured, smooth, light yellowish green. Excipulum entire, prosoplectenchymatous, brown to dark brown, 15-20 µm wide, fused with thalline margin and difficult to separate from the bordering periderm; laterally covered by algiferous, corticate thallus containing periderm layers; columella present, finger-like, carbonized, up to 100 µm broad and 120-135 µm high; hypothecium prosoplectenchymatous, 5-10 µm high, hyaline; hymenium 125-140 µm high, hyaline, clear; epithecium indistinct, 5-10 µm high, hyaline. Paraphyses unbranched, apically smooth; periphysoids absent; asci cylindrical to narrowly clavate, 87-100 × 12-15 µm. Ascospores 8 per ascus, ellipsoid, 5-7-septate, 20-23 × 7-8 µm, hyaline, distoseptate with lens-shaped lumina, I+ violet-blue. Pycnidia not seen.

Secondary chemistry.

No substances detected by TLC.

Distribution and ecology.

The new species was collected in northeastern Thailand, growing on bark in a dry evergreen forest. It is known only from the type locality.

Remarks.

This new species is closely related to Ocellularia albocincta (Fig. 2). However, this species differs in lacking a columella ( Papong et al. 2010). Morphologically it resembles Ocellularia viridipallens , which differs in having narrower ascospores. The species would key out at alternative 60 in the Ocellularia key for Thailand ( Sutjaritturakan and Kalb 2015).

Additional specimen examined.

THAILAND, Ubon Ratchathani Province, Pha Tam National Park, trail to Huai Sanom, 15°27'N, 105°34'E, 245 m, dry evergreen forest, on bark; 12 April 2013, K. Papong 8439 ( MSUT).