Pseudostegia Bubák, J. Mycol. 12(2): 56 (1906)
Facesoffungi number: FoF 07547
Ascomycota, genera incertae sedis
Saprobic on dead leaves of Carex sp. (Cyperaceae) (Sutton 1980). Sexual morph: undetermined. Asexual morph: Conidiomata dark brown to black, stromatic, solitary or confluent, subepidermal, immersed, applanate, disciform, unilocular, glabrous. Ostiole indistinct, dehiscence by circumscissile rupture of the upper wall lifting off a flap of tissue. Conidiomatal wall composed of thick-walled, dark brown cells concentrated in the epidermis in the upper part, becoming thick-walled, brown, relatively large cells of textura globulosa in the lower part, gradually diminishing in size and pigmentation towards the conidiogenous cell region. Conidiophores reduced to conidiogenous cells. Conidiogenous cells pale brown, enteroblastic, phialidic, ampulliform to cylindrical, determinate, smooth-walled, with conspicuous, periclinal wall thickened channel and collarette, arising from the inner wall layer of basal stroma. Conidia hyaline, falcate, unicellular, smooth-walled, eguttulate (adapted from Sutton 1980).
Type species: Pseudostegia nubilosa Bubák, J. Mycol. 12(2): 56 (1906)
Notes: Pseudostegia is monotypic. The hyaline, falcate, unicellular conidia in Pseudostegia invite a comparison with Colletotrichum and Pseudoseptoria. Pseudoseptoria has pycnidial conidiomata and annellidic, subcylindrical to ampulliform conidiogenous cells, which differs from the acervular conidiomata and phialidic, ampulliform to cylindrical conidiogenous cells in Colletotrichum and Pseudoseptoria (Sutton 1980). Pseudoseptoria was separated from Colletotrichum by its method of conidiomatal wall dehiscence (Sutton 1980). However, this character alone may not be enough to separate it from Colletotrichum. An epitype of Pseudostegia nubilosa is needed to confirm its placement.
Distribution: USA (Sutton 1980).
Pseudostegia nubilosa (redrawn from Sutton 1980) a Conidia. b Conidiogenous cells and developing conidia. c Vertical section of conidioma.
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.