Index Fungorum number: IF550706, Facesoffungi number: FoF00165 (Figure 5).

Etymology: —Species name refers to the host genus Tectona, from which the fungus was first collected.

Saprobic on dead branch of Tectona grandis. Sexual morph: Undetermined. Asexual morph: Conidiomata (225–) 365–400 (–490) μm high × (170–) 270–300 (–325) μm diam. (x = 355 × 260 μm n = 10), pycnidial, black, initially immersed, becoming erumpent through bark fissures, solitary to gregarious, uniloculate, subglobose, papillate. Papilla up to 70 μm long, 50–60 μm diam., ostiole central, periphysate. Conidiomata wall 30–105 μm thick at sides, up to 100 μm thick at base, outer layers thickened and dark, inner layer dark brown to hyaline, composed of several layers of cells of textura angularis. Conidiogenous cells (6–) 10–12 (–15) × (3.5–) 6–6.5 (–7.5) μm (x = 10.5 × 6 μm n = 20), holoblastic, discrete, hyaline, obovoid to ellipsoidal, smooth-walled. Conidia on host (16–) 21–22 (–24) × (7.5–) 10–11 (–13) μm (x ± S.D. = 21 ± 1.9 × 10 ± 1.2 μm, n = 50), initially hyaline and aseptate, becoming light brown to dark brown and aseptate, or 1–septate while still attached to conidiogenous cells, 1–septate at maturity, slightly constricted at the septum, oblong to ellipsoidal, ends rounded, bases obtuse, with short raised irregular striations on the surface, thick-walled, with granular content. Spermatogenous cells discrete, hyaline, smooth-walled, cylindrical, holoblastic. Spermatia 2.5–4 × 1–2 μm hyaline, aseptate, smooth, rod-shaped, with rounded ends.

Culture characteristics: —Conidia germinating on PDA after 16 h. Germ tubes produced from both ends of conidia or produced laterally in some conidia. Colonies on MEA reaching 45 mm diam after 2 days in the dark at 25 °C, flattened or effuse, undulate, initially white, after 2 days becoming brownish grey (8F2) in the centre, white at edge, reaching the edge of the Petri-dish after 4 days. Cardinal temperatures for growth after four days: optimum 25–30°C, 1 mm at 5°C, 5 mm at 15°C, 8 mm at 25°C, 7 mm at 30°C.

Material examined: — THAILAND, Phayao Province, Muang District, on dead branch of Tectona grandis (Lamiaceae), 12 March 2012, M. Doilom (MFLU 14-0272, holotype), ex-type culture, MFLUCC 12-0382, MUCL 55409.

Notes: — Dothiorella tectonae is introduced here as a novel species based on its morphological and phylogenetic differences from known Dothiorella species. Do. tectonae differs from Do. brevicollis and Do. longicollis in having short raised irregular striations on the surfaces of mature conidia. Conidia of Do. tectonae are shorter and narrower than Do. brevicollis, but longer and wider than those of Do. longicollis (Table 4). Short raised irregular striations can also be found on conidia of Do. thailandica, however, mature conidia of Do. tectonae are longer and wider than those of Do. thailandica. Dothiorella tectonae has papillate conidiomata while Do. thailandica conidiomata are nonpapillate (Table 4).