Collarispora Videira & Crous, in Videira et al., Stud. Mycol. 87: 325 (2017).
Pathogenic, causing leaf spots. Sexual morph: Ascostromata amphigenous, black, erumpent through epidermis, thick-walled, composed of several layers of textura angularis, ostiole central, periphysate. Asci 8-spored, bitunicate, fasciculate, ellipsoid, straight to incurved, with apical chamber. Ascospores hyaline, smooth, fusoid-ellipsoidal, medianly uniseptate, guttulate, slightly incurved, widest just above septum, tapering towards both acutely rounded ends, thick-walled; ascospores germinate from both ends, germ tubes parallel to the long axis of the spore, lateral branches also developing, becoming constricted at median septum, but remaining hyaline. Asexual morph: Mycelium consisting of hyaline, smooth, septate and branched hyphae. Conidiogenous cells terminal on hyphae, hyaline, subcylindrical, smooth, conidiogenous loci not thickened nor darkened. Conidia solitary, subcylindrical to narrowly obclavate, straight to flexuous, apex obtuse, base truncate, multiseptate, hila not thickened nor darkened, with visible marginal frill; with age conidia tend to become pale olivaceous and finely verruculose (adapted from Videira et al. 2017).
Type species: Collarispora valgourgensis (Crous) Videira & Crous
Notes: Collarispora is characterised by amphigenous, black ascostromata, fasciculate, ellipsoid 8-spored asci, and smooth, fusoid-ellipsoidal, hyaline ascospores. The sexual morph of Collarispora valgourgensis is Mycosphaerella-like, and the asexual morph is pseudocercospora-like (Crous et al. 2011). The asexual morph of Collarispora valgourgensis differs from Pseudocercospora by producing subcylindrical to narrowly obclavate conidia that are primarily hyaline turning pale brown and verruculose, with a basal marginal frill. Collarispora is closely related to Cercosporidium but differs in that the latter has narrowly obclavate and verruculose conidia and lack a basal marginal frill. Collarispora is a distinct and well-supported genus in Mycosphaerellaceae. Molecular markers available for Collarispora are ITS, LSU and RPB2.