Glaucotrema thailandicum 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

Glaucotrema thailandicum Naksuwankul, Luecking & Lumbsch sp. nov. Figure 3 A–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 8560 (holotype: MSUT; isotype: F).

Diagnosis.

Characterized within the genus by having submuriform ascospores.

Etymology.

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

Description.

Thallus endophloeodal to epiphloeodal, up to c. 120 µm thick, pale green to yellowish green, smooth. True cortex ± continuous, to c. 25 µm thick. Algal layer poorly to well developed, ± continuous; calcium oxalate crystals sparse to abundant, large and clustered; medulla usually distinct. Vegetative propagules not seen. Ascomata conspicuous, to c. 0.8-1.2 mm diam., often larger when fused, ± rounded to irregular, apothecioid to somewhat chroodiscoid, solitary to more often fused, becoming slightly to distinctly emergent, mostly irregularly or regularly urceolate. Disc usually partly visible from above, rarely completely exposed, pale yellowish to whitish green. Pores broad to gaping, to c. 0.6-08 mm wide, ± rounded to irregular, entire to slightly ragged; thalline exciple often becoming apically visible, rarely completely visible from above, ± free, whitish. Thalline rim margin broad to gaping, ± rounded, more commonly irregular, thick, entire, concolorous to whitish. Thalline exciple fused to partly or entirely free, thick, hyaline internally, pale yellowish or greenish marginally, with calcium oxalate crystals. Hymenium to c. 120 µm thick, clear, strongly conglutinated; paraphyses thick, irregular and often distoseptate, ± interwoven, with thickened irregular tips; lateral paraphyses absent; columella whitish and reticulate. Epihymenium hyaline, with fine crystals. Asci 8-spored; tholus initially thick, thin when mature, 100-110 × 10-12 µm. Ascospores submuriform with 3 × 0-1 septa, hyaline, slightly amyloid, 15-20 × 7.5 µm. Pycnidia not seen.

Secondary chemistry.

Thallus K+ yellowish, C–, P+ yellow; containing psoromic acid.

Distribution and ecology.

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

Remarks.

This new species is unique within the genus in having submuriform ascospores, whereas all other described species have transversely septate ascospores. In addition, the ascospores in Glaucotrema bahianum , Glaucotrema costaricense and Glaucotrema stegoboloides are smaller than in the new species. Molecular data support the distinction of the new taxon. In morphology it resembles Glaucotrema bahianum and Glaucotrema stegoboloides .