Septoria Sacc., Syll. fung. (Abellini) 3: 474 (1884).
Index Fungorum number: IF 9894; Facesoffungi number: FoF 07588, 579 morphological species (Species Fungorum 2021), > 100 species with molecular data.
Pathogenic on host. Sexual morph: Mycosphaerella-like. Asexual morph: Mycelium slow-growing, pale brown, septate, immersed. Conidiomata pycnidial, immersed, separate or aggregated (but not confluent), globose, papillate (or not), brown, thin wall comprising of pale brown cells of textura angularis, inner layer of flattened, hyaline textura angularis, frequently somewhat darker and more thick-walled around the ostiole. Ostiole single, circular, central. Conidiophores reduced to conidiogenous cells. Conidiogenous cells holoblastic, either determinate or indeterminate, proliferating sympodially and/or percurrently, hyaline, smooth, ampulliform, dolliform or lageniform to short cylindrical; scars unthickened. Conidia hyaline, multiseptate, filiform, smooth, continuous or constricted at septa (adapted from Quaedvlieg et al. 2013).
Type species: Septoria cytisi Desm.
Notes: Septoria cytisi was first described by Desmazières (1847) as a pathogen of Cytisus laburnum (= Laburnum anagyroides). Septoria is a very large genus and comprises more than 500 taxa. Many species of Septoria have mycosphaerella-like sexual states. Morphological characters to describe Septoria species are limited. Feau et al. (2006) was the first to provide molecular data to identify Septoria species. Quaedvlieg et al. (2011) demarcated Septoria by providing sequence data from S. cytisi herbarium specimens. Currently, Septoria is polyphyletic in Mycosphaerellaceae. Molecular markers available for Septoria are ITS, LSU, SSU, Actin, BTUB, Calmodulin, Histone, RPB2 and TEF-1.