Ocellularia klinhomii Naksuwankul, Luecking & 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 : 51-52

Ocellularia klinhomii Naksuwankul, Luecking & Lumbsch sp. nov. Figure 3 F–K

Type.

THAILAND, Ubon Ratchathani Province, Pha Tam National Park, Sang Chan waterfall, 15°30'N, 105°35'E, 124 m, dry evergreen forest, on bark; 12 April 2013, K. Papong 8566 (holotype: MSUT; isotype: F).

Diagnosis.

Differing from the similar Ocellularia krathingensis in having a whitish grey, rimose thallus.

Etymology.

The specific epithet refers to the collector Mr. Winia Klinhom, mycologist from Thailand.

Description.

Thallus corticolous, epiperidermal, up to c. 5 cm diam., continuous; surface rimose, whitish grey, medulla white; prothallus absent. Thallus in section 30-40 µm thick, with prosoplectenchymatous cortex, 5-10 µm thick, photobiont layer 15-20 µm thick, and medulla 20-25 µm thick, with scattered clusters of calcium oxalate crystals. Photobiont Trentepohlia ; cells rounded to irregular in outline, in irregular groups, green, 7-9 × 6-8 µm. Ascomata rounded, verrucae and surrounded by a black ring, erumpent to immersed, with complete thalline margin, 0.4-0.7 mm diam., 0.15-0.2 mm high; disc covered by 0.05-0.1 mm wide pore more or less filled with black-tipped columella but columella often immersed; proper margin indistinct, entire to slightly fissured, visible as whitish rim around the pore; thalline margin entire to slightly fissured, smooth, yellowish green. Excipulum entire, prosoplectenchymatous, brown with apically carbonized, 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 120-140 µm high; hypothecium prosoplectenchymatous, 5-10 µm high, light brown; hymenium 125-150 µm high, hyaline, clear; epithecium indistinct, 5-7 µm high, hyaline. Paraphyses unbranched, apically smooth; periphysoids absent; asci cylindrical to narrowly clavate, 110-115 × 12-15 µm. Ascospores 8 per ascus, ellipsoid, 6-9-septate, 25-38 × 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.

Similar in ascospore size, lack of secondary metabolites and only apically carbonized exciple to Ocellularia krathingensis but differing in having a whitish gray, rimose thallus with ascomata in verrucae and surrounded by a black ring, reminiscent of Ocellularia wirthii ( Mangold et al. 2008). The latter species is readily distinguished by having a broader, carbonized columella and the presence of the psoromic acid chemosyndrome. 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, Sang Chan waterfall, 15°30'N, 105°35'E, 124 m, dry evergreen forest, on bark; 12 April 2013, K. Papong 8568, 8552, 8567, 8570, 8542, 8541, 8573, 8574 ( MSUT), K. Papong 8557 ( RAMK).