Stirtonia curvata
Stirtonia curvata is a crusty lichen in the Arthoniaceae family. It was described as a new species in 2009 from specimens collected in Indonesia. The name curvata comes from the curved shape of its spores. Dutch lichenologist André Aptroot described it from samples collected by Willem Vink near Manokwari, western New Guinea, in 1959.
The genus Stirtonia has lichens with special reproductive areas that lack a true spore-producing layer, round asci, and thick-walled, multi-septate spores. Stirtonia curvata forms a smooth, crust-like thallus that sticks to tree bark, up to about 5 cm across. It is whitish-yellow to brownish, very thin (<0.1 mm), and somewhat shiny. The thallus contains calcium oxalate crystals visible under a microscope.
The reproductive areas appear as angular or linear zones on the surface, sometimes branched, slightly raised, about 0.1–0.2 mm wide and up to 1 mm long. They are white and fibrous, and rubbing them can leave reddish-brown or black dots. No algal cells are found in these zones.
Under the microscope, the asci are oval and typically hold four to eight ascospores. The ascospores are ellipsoid, 35–55 μm long and 12–19 μm wide, with 7–11 transverse septa, often curved. They have thick walls and septa, each over 1 μm thick.
In iodine stain, the lower portions around the asci turn blue, while the upper portions turn violet. Chemically, the lichen contains perlatolic acid. It does not react to common chemical spot tests.
Stirtonia curvata grows on tree bark in tropical lowland forests. It has been found in Western New Guinea and Java, Indonesia, at very low elevations (around 2 meters above sea level). It is considered locally rare or not often collected, probably because it is not widely recorded.
This page was last edited on 2 February 2026, at 20:52 (CET).