Astrothelium globosum
Astrothelium globosum is a species of lichen in the family Trypetheliaceae. This species is characterised by its immersed ascomata and a thallus consisting of nearly spherical warts, along with distinctive 3-septate ascospores.
Taxonomy
Astrothelium globosum was formally described as a new species in the journal The Lichenologist in 2016. The type specimen was collected in, Mata do Crasto, Brazil, on the bark of a tree, in March 2012.Description
The thallus of Astrothelium globosum is, consisting of closely appressed, nearly spherical warts measuring 0.3–0.9 mm in diameter. These warts form a pale greyish-green cover over areas up to 3 cm in diameter and are approximately 0.9 mm thick. The thallus has a thick hyaline and does not induce gall formation on the host bark. are pyriform, measuring 0.2–0.4 mm in diameter, and usually appear in groups of 2–5, immersed in the bark and visible from above by black ostioles between the thallus warts. The ascomata wall is and up to 50 μm thick. Ostioles are eccentric and brown. The is not inspersed, and are 8 per ascus, hyaline, 3-septate, long ellipsoid, 35–40 by 11–13 μm, with diamond-shaped and surrounded by a gelatinous sheath. were not observed in this species.This species is distinguished by a unique thallus consisting of almost spherical warts, an unusual three-dimensional feature for a crustose lichen. It is most closely related to Astrothelium simplex, which is differentiated by its longer ascospores.