Trypethelium infraeluteriae

The thallus is corticate, smooth, somewhat shiny, and continuous, covering areas up to at least 5 cm in diameter and about 0.1 mm thick. It is olive-greenish grey and lacks both a visible prothallus and gall formation on the host bark.^[2]

The sexual fruiting bodies (ascomata) are more or less spherical (globose), 0.3–0.5 mm in diameter, and grouped in clusters of 6–15 within pseudostromata. These pseudostromata differ in appearance from the surrounding thallus, being slightly raised, irregular to linear in outline, sometimes forming a net-like structure, and orange in colour. The walls are dark brown, up to about 50 micrometres (μm) thick. Each ascoma has a small apical pore (ostiole) that is flat to concave and grey. Internally, the hamathecium is clear and colourless, without oil droplets. Asci contain eight spores each. The spores are colourless, spindle-shaped (fusiform), 7–9-septate, 37–42 × 9–11 μm, with pointed ends and ellipsoid internal cavities (lumina); they lack a gelatinous sheath.^[2]

The thallus does not fluoresce under ultraviolet light (UV−) and gives negative reactions with potassium hydroxide solution (K−). In contrast, the pseudostroma surface and interior react positively with potassium hydroxide (K+ red). Thin-layer chromatography detected the presence of parietin, emodin, and two related anthraquinone derivatives.^[2]

Trypethelium infraeluteriae grows on bark of trees, including in plantations and along roadsides. It is known only from Cát Tiên National Park in southern Vietnam.^[2]