Celothelium A. Massal.
Atti Reale Ist. Veneto Sc. Lett. Arti, ser. 3, 5: 332, 1860.
Systematics:
Phylum: Ascomycota Caval.-Sm.
Subphylum: Pezizomycotina O.E.Erikss. & Winka
Class: Eurotiomycetes O.E.Erikss. & Winka
Subclass: Chaetothyriomycetidae Dowell
Order: Phaeomoniellales K.-H.Chen, A.E.Arnold, Gueidan & Lutzoni
Family: Celotheliaceae Lücking, Aptroot & Sipman
Brief description: Thallus crustose, endosubstratic, poorly evident. Perithecia black, shiny, scattered or clustered in small groups, circular to ellipsoid, at first immersed, then projecting, hemispherical to flattened, dimidiate, the ostiole located in a small central papilla. Involucrellum blackish, covering groups of perithecia, composed of bark material mixed with reddish-brown, thick-walled, smooth hyphae, forming a clypeus of textura epidermoidea; exciple intergrading with the involucrellum, mainly differentiated at the margins of perithecia, sometimes extending below, of colourless to brown hyphae intermixed with bark cells forming a textura intricata; hamathecium of branched and anastomosing paraphysoids, periphyses absent; hymenial gel hemiamyloid. Asci 8-spored, cylindrical, bitunicate, the outer layer thin and smooth, the inner without an apparent internal apical beak, I- but with a meniscus staining I+ dark blue near the apex. Ascospores multiseptate, hyaline, twisted in the asci, thread-like to needle-like, with pointed apices. Pycnidia immersed to superficial, dark brown to black, the conidiogenous cells elongate-bottle-shaped, lining the cavity. Conidia multiseptate, hyaline, thread-like. Photobiont: trentepohlioid. Chemistry: mostly without lichen substances.
Note: A genus with 8 species, most diverse in the tropics, where species are epiphytic on branches in rainforest and in coastal areas (Aguirre-Hudson 1991). Its status in the Celotheliaceae, as the sister group of the Pyrenulaceae, has been confirmed by molecular analyses (see e.g. Aptroot & al. 2008, Gueidan & al. 2014b). Only one species is known from Italy.
Type: Celothelium socialis (Zenker) A. Massal.
