Anamorph: reported as Stagonospora vexata, but the connection has not been confirmed. Lucas (1968) found that the species produces ascomata and ascospores in culture, but no anamorph.
Teleomorph: ascostromata perithecial, 0.1-0.25 mm diam., globose to oblate, often elongated parallel to the long axis of the substratum, without a papilla, subcuticular, becoming ± superficial, gregarious, frequently forming raised longitudinally elongate groups, and then with a well-developed dark clypeus that is continuous between ascomata. Peridium 16-20 µm thick, glabrous, composed of compressed to polygonal cells, inwardly thicker and sometimes with elongate cells around the ostiole. Interascal tissue of numerous narrow cellular pseudoparaphyses ca 1.5 µm diam. Asci 60-100 x 13-16 µm, clavate, thick-walled and fissitunicate, 8-spored. Ascospores 26-34 x 4-5 µm, cylindrical-fusiform, hyaline and sometimes later brownish when over-mature, 1- to 3-septate, with the segment immediately above the primary septum slightly swollen, with a broad gelatinous sheath visible in some collections.
Not formally assessed, but this appears to be a common and widespread species.
Characterised by the clypeus which is continuous between ascomata giving a somewhat stromatic appearance and by the cylindrical-fusiform ascospores with a basal cap.
Most commonly found on dead leaves and culms of Phragmites australis, also reported on Elymus, Elytrigia spp and Phalaris arundinacea. Records on Poa need confirmation.
In GB&I, reported from England (Buckinghamshire, Cornwall, S Devon, Durham, W Gloucestershire, S Hampshire, Huntingdonshire, S Lancashire, W Norfolk, Northamptonshire, Shropshire, E Suffolk, Surrey, Westmorland, N Wiltshire, SE Yorkshire, W Yorkshire), Wales (Brecon, Pembrokeshire), Channel Is, Ireland (E Cork, Dublin, N Kerry) and Scotland (Roxburgh, M Ebudes, N Ebudes).