Sometimes seen on dead leaves or on leaf spots; in the latter case Arthrinium spp. are probably secondary invaders of damaged tissue. A. arundinis has been reported to cause kernel blight of barley.
Morphology
Conidiophores brown to dark brown, arising from hyphae or aggregated in a brown stroma, forming black sporodochia. Setae present or absent, brown, intermingled among conidiophores. Conidia aseptate, brown to dark brown, smooth to verruculose, of various sizes and shapes; globose, ellipsoidal, lenticular, angular, kidney-shaped, lobed or dentate in surface view, sometimes with a small basal scar; often lenticular in side view with a pale equatorial ridge (germ slit). Ascomata immersed, solitary or aggregated in rows, often subglobose, brown to dark brown; ostiole single, central. Asci 8-spored, unitunicate, thin-walled. Ascospores hyaline, smooth, bi- to tri-seriate, apiosporous and 1-septate near the lower end.
Notes
Crous & Groenewald (2013) reviewed the genus, provided a molecular phylogeny and described several new species. They also found that the presence or absence of stromata and setae were not characters that could be used to separate the genera Cordella and Pteroconium. Some of the new species are barely separable on morphological characters and a DNA sequence is necessary to distinguish many of the species.
