Atopospora Petr., Annls mycol. 23(1/2): 100 (1925).
Index Fungorum number: IF 450; Facesoffungi number: FoF 06356, 4 morphological species (Species Fungorum 2022), no molecular data available.
Saprobic on host. Sexual morph: Stroma subcuticular, black, with several ascogenous globose locules in a single layer. Asci cylindrical-clavate, 8-spored. Ascospores ellipsoidal to cylindrical, septate towards the upper end of the spore, not or very slightly constricted at the septum, initially hyaline, becoming yellowish to olivaceous when mature (adapted from Fakirova 1997). Asexual morph: conidiomata acervular, subcuticular, formed in the upper layer of the stroma, flattened or flattened-pulvinate, the upper wall composed of a thin layer of black fungal cells with the host cuticle outside, rupturing irregularly to release the conidia. Lower wall composed of mid brown prismatic cells, not well differentiated from the stromatic tissue. Conidiophores arranged in a palisade-like layer, poorly developed, cylindrical, straight, sometimes septate, brown, each producing a single conidiogenous cell. Conidiogenous cells cylindrical, holoblastic, proliferation uncertain, pale brown, sometimes verruculose towards the apex. Conidia irregularly curved and with an attenuated apex, the apex truncate, with a median or slightly submedian septum, pale brown, smooth or faintly verruculose, without a gelatinous sheath or appendages (adapted from Fungi of Great Britain and Ireland 2022).
Type species: Atopospora betulina (Fr.) Petr.
Notes: Atopospora is characterised by subcuticular black stromata with numerous acrogenous globose, cylindrical-clavate, 8-spored asci and ellipsoidal to cylindrical, septate ascospores. Müller and Arx (1962) referred Atopospora to Venturiaceae based on the multiloculate ascostromata, fusoid asci and lightly pigmented, bi-seriate, apiospores. Molecular data is lacking. Fresh collections with DNA sequence data are needed to confirm the systematic position of Atopospora.