Halegrapha paulseniana
Halegrapha paulseniana is a species of bark-dwelling script lichen in the family Graphidaceae. It forms a cream-white crust on tree bark and produces elongated, branching, script-like fruiting bodies with a partly exposed dark. The species was described in 2018 and was the first member of its genus recorded from Hawaii. It is known only from montane forest on the slopes of Haleakalā volcano on Maui, where it may be endemic.
Taxonomy
Halegrapha paulseniana was described as new to science in 2018 by Rubin Michael Luch and Robert Lücking, based on a collection made in 2013 on the island of Maui in the lower Waikamoi Preserve on the slopes of Haleakalā. Its description also represented the first documented record of the genus Halegrapha from the Hawaiian Islands.The species belongs to Halegrapha, a genus of tropical Graphidaceae with a script lichen appearance but brown, Phaeographis-type spores. In the original treatment, H. paulseniana was distinguished from the most similar species, H. mexicana, by its much larger lirellae that retain a complete, thin at the apex; it was separated from other members of the genus by the, which is often not fully along the sides. The specific epithet honors the German educator and philosopher Friedrich Paulsen, regarded as one of the founders of modern higher secondary education in Germany, and the namesake of the.
Description
Halegrapha paulseniana is a bark-dwelling, crustose lichen that forms a continuous, uneven, cream-white thallus up to about across. In section, the thallus has a thick upper layer over an irregular and a distinct medulla, and parts of the thallus are encrusted with grayish crystals; the thallus tissue over the fruiting bodies can contain clusters of calcium oxalate crystals. The is Trentepohlia.The fruiting bodies are that are and irregularly branched, typically 3–8 mm long. They break through the thallus surface and have a thalline margin that is thick on the sides but thin at the top. The is partly exposed and dark brown to nearly black, with entire . The excipulum is largely carbonized, but the lateral portions are often only weakly carbonized or uncarbonized. The asci contain eight spores; the ascospores are oblong to oval, usually 5–7-septate, about 20–25 × 7–8 μm, and turn brown at maturity. No lichen substances were detected by thin-layer chromatography.