Pyrenula triangularis

This species was described as new by Harrie Sipman and André Aptroot in 2013. The holotype was collected in Serra dos Órgãos National Park (Rio de Janeiro state, Brazil) at roughly 1,600–2,000 m elevation, along the track from Abrigo 2, on tree bark. The authors distinguished it from similar species such as P. circumfiniens based on spore features and by differences in ostiole position and development. The species epithet triangularis alludes to the often triangle-shaped . ==Description==

This species produces a very thin, gray‑brown crust framed by a narrow black line. Its perithecia are conical and sit on the surface, measuring 0.6–1.0 mm across. They usually occur in groups of two to four; the perithecia in a group merge their walls and pores to form a single superficial mass (a pseudostroma) that often looks triangular from above. In vertical section each conical component is 1.0–2.0 mm wide. The pores are lateral rather than apical and are often depressed and whitish. The is clear, without oil droplets. Each ascus yields eight ascospores arranged in two rows. The spores are —divided by five transverse walls and one to three longitudinal walls—and measure 25–31 μm long and 12–16 μm wide. Their internal cavities are rounded, and a thickened inner wall is present at the tips. No asexual structures are known in this species. ==Habitat and distribution==

As of its original description, Pyrenula triangularis was known only from the type collection in Guyana. No additional location were reported by Aptroot in his 2021 world key to the genus. ==See also==