Ocellularia rotundifumosa Naksukankul, 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 : 53-55

Ocellularia rotundifumosa Naksukankul, Luecking & Lumbsch sp. nov. Figure 4 C–E

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 8576 (holotype: MSUT; isotype: F).

Diagnosis.

Differing from Ocellularia fumosa in having ascospores with rounded ends.

Etymology.

The specific epithet refers to the ascospore shape with rounded ends and to the similarity with Ocellularia fumosa .

Description.

Thallus corticolous, endophloeodal to epiphloeodal, up to c. 200 µm thick, greenish gray to olive, slightly glossy, smooth, rarely continuous to usually ± verrucose. True cortex discontinuous, to c. 15 µm thick, formed by irregular hyphae. Algal layer well developed, continuous; calcium oxalate crystals moderately large, scattered. Photobiont Trentepohlia ; cells rounded to irregular in outline, in irregular groups, green, 7-9 × 6-9 µm. Vegetative propagules not seen. Ascomata rounded with complete thalline margin, 0.4-0.9 mm diam., solitary to marginally fused, immersed to rather emergent, then verrucose-hemispherical to urceolate. Disc with the columella visible from above, entire, free, slightly pruinose, dark gray. Pores formed by the thalline rim margin, c. 0.5 mm diam., the apex of the proper exciple becoming visible from above as a brownish to dark gray line, moderately thick, concolorous with the thallus or brighter; thalline rim incurved. Proper exciple fused, dark brown to carbonized marginally and towards the tips, usually distinctly amyloid at the base. Hymenium to c. 150 µm thick, densely inspersed, distinctly conglutinated; paraphyses slightly bent, ± interwoven, unbranched, with moderately thickened tips; columellar structures moderately well developed, to 150 µm wide, entire, the upper parts brownish to carbonized. Epihymenium brownish, with grayish or brownish granules. Asci 8-spored; tholus initially thick, thin when mature. Ascospores 7-9-septate, fusiform to oblong-fusiform, rarely clavate, with rounded ends, 24-35 × 7-10 µm, hyaline, distoseptate with lens-shaped lumina, I+ violet-blue. Pycnidia not seen.

Secondary chemistry.

No compounds detectable 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 to Ocellularia fumosa , but differing in having rounded ends of the ascospores instead of acute ones in Ocellularia fumosa . Molecular data support the distinction of the species (Fig. 2). Characters to separate the related Ocellularia natashae and Ocellularia thryptica are discussed above. The species would key out at alternative 23 in the Ocellularia key for Thailand ( Sutjaritturakan and Kalb 2015).