Annulatascus K.D. Hyde
Sexual morph: Ascomata clustered or separate, brown to black, superficial, semi-immersed or immersed, solitary or gregarious, globose or subglobose, immersed or semi-immersed, carbonaceous or coriaceous, ostiolate, periphysate. Peridium comprising several layers of cells of textura angularis, or pseudoparenchymatous, or melanized angular cells. Hamathecium comprising paraphyses which are hyaline, septate and taper distally. Asci 8-spored, unitunicate, cylindrical, pedicellate, with a massive bi-partite apical ring. Ascospores unicellular to multi-septate, uni-seriate to overlapping bi-seriate, ellipsoidal or fusiform or lunate or citriform, hyaline to pale brown, verrucose or smooth, guttulate or non-guttulate, with or without sheath and appendages. Asexual morph: Undetermined.
Notes: This genus is cosmopolitan, and has been described on submerged substrata, such as submerged decaying wood, stems of Phragmites australis, and dead petioles of Licuala ramsayi and bamboo. Currently Annulatascus comprises 16 species. Annulatascus is known to be polyphyletic according to LSU rDNA sequence data (Raja et al. 2003, Campbell and Shearer 2004, Abdel-Wahab et al. 2011). Tsui and Hyde (2003) provided a key to species and a synoptic table of 12 Annulatascus species based on morphological characteristics. Boonyuen et al. (2012) provided comparative table of morphological features for 16 Annulatascus species.
Type species: Annulatascus velatisporus K.D. Hyde, Aust. Syst. Bot. 5(1): 118 (1992).