Astrothelium | |
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Astrothelium aeneum found in Florida | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Dothideomycetes |
Order: | Trypetheliales |
Family: | Trypetheliaceae |
Genus: | Astrothelium Eschw. (1824) |
Type species | |
Astrothelium conicum Eschw. (1824) | |
Synonyms [1] | |
Astrothelium is a large genus of corticolous (bark-dwelling) lichens in the family Trypetheliaceae. [2] The genus is characterized by a corticate thallus and diverse ascomata structures, which can be simple, aggregated, or forming pseudostromata . Astrothelium is also notable for the carbonized walls of its ascomata, the so-called textura intricata (i.e., tightly interwoven) arrangement of cells in these walls, and various forms of distoseptate , transparent spores.
The genus was circumscribed in 1824 by German botanist Franz Gerhard Eschweiler, with Astrothelium conicum assigned as the type species. [3]
The thallus, or the vegetative body of Astrothelium, is corticate , meaning it is covered by a protective cortex . The ascomata, which are the fruiting bodies containing the reproductive spores, can appear in various forms such as simple, aggregated, or forming pseudostromata . These structures often differ in their composition and colour, and can be used as characters to distinguish between species. The ascomata can range from being immersed within the thallus to prominently displayed on the surface. The ostioles, or small openings that allow the release of spores, can be located at the apex or eccentrically on the ascomata and may appear as either simple or fused structures. [4]
Astrothelium is also notable for its ascomatal wall, which is made up of hyphal cells and is typically carbonized. The wall features a textura intricata , a term used to describe a tightly interwoven arrangement of cells. [4]
Within the hamathecium , the tissue that houses the asci (spore-producing structures), the cells are either clear or filled with oil droplets. The ascospores, which are the sexual spores responsible for reproduction, are distoseptate and hyaline in appearance. They can also exhibit a variety of forms, including transversely septate or muriform , reflecting their segmented or multi-cellular nature. [4]
As of January 2024 [update] , Species Fungorum accepts 267 species in Astrothelium. [5]