Index Fungorum number: IF 804423; Facesoffungi number: FoF 08538, 1 morphological species (Species Fungorum 2022), 1 species with molecular data.
Saprobic or pathogenic on host. Sexual morph: Unknown. Asexual morph: Leaf spots numerous, small, angular, and frequently merging to irregular patterns, visible on both sides of the leaf, at first pale yellowish brown, becoming reddish brown with a narrow, darker border. Conidiomata pycnidial, hypophyllous, numerous in each leaf spot, subglobose to lenticular, very pale brown to dark brown, generally fully immersed, releasing conidia in white cirrhi. Ostiole not well-differentiated, central, circular, surrounding cells concolorous. Conidiomatal wall comprise of a homogenous tissue of hyaline to very pale brown, angular to irregular cells. Conidiophores subcylindrical, branched at base, hyaline, smooth, 1–2-septate; base frequently brown, verruculose. Conidiogenous cells hyaline, discrete or integrated in conidiophores cylindrical or narrowly ampulliform, holoblastic, often proliferating per currently with up to 3 closely positioned annellations. Conidia cylindrical, slightly to distinctly curved, irregularly bent or flexuous, with a relatively broadly rounded apex, attenuated towards a truncate base, basal and apical cell often both wider than intermediate cells, (0–)2–3(–4)-septate, mostly constricted around the septa in the living state, hyaline, contents with several oil-droplets and granular material in each cell in the living state, with granular contents in the rehydrated state. Conidia are olivaceous-brown in mass, and older conidia also turn olivaceous and verruculose, and at times anastomose in culture (adapted from Quaedvlieg et al. 2013).
Type species: Stromatoseptoria castaneicola (Desm.) Quaedvl., Verkley & Crous
Notes: Stromatoseptoria differs from Septoria in having a central cushion or stroma that gives rise to conidiophores and olivaceous-brown conidia which turn to olivaceous and verruculose when mature. Stromatoseptoria is a distinct and well-defined genus in Mycosphaerellaceae. Molecular markers available for Stromatoseptoria include ITS, LSU, SSU, BTUB, TEF-1 and RPB2.