Anamorph: conidiomata absent. Conidiophores reduced to conidiogenous cells, developing in clusters from stomata of the host plant, (5.5–) 12–15 (–27) × (1.5-) 2–3 μm, cylindrical or sometimes narrower towards the apex, hyaline, thin-walled, smooth, with 1–2 thickened, darkened, refractive apical conidiogenous loci ca 1 μm diam. Conidia formed in easily fragmented chains, 17-25 x 2.5-3 µm, cylindrical, the ends obtuse, mostly 0- or 1-septate, hyaline, smooth, thin-walled, without a gelatinous sheath or appendages.
Teleomorph: not known.
Not formally assessed, but the species is common and widespread.
On living leaves of Rumex species, also occasionally recorded on Rheum rhabarbarum.
Throughout Great Britain and Ireland, also in the Channel Is.