Anamorph: Microxiphium sp. Colonies composed of hyphae with many constricted septa, hyphal cells rounded. Setae to 230 µm widening to 6-10 µm at the base, straight, tapering, acute, dark brown, simple, smooth, with a bulbous base, inserted in a small pad of brown-walled polyhedral cells and sheathed with a cortex of hyphae. Conidiomata absent, conidiogenesis localised on the upper part of the setae. Conidiogenous cells integrated, determinate, blastic, possibly phialidic, intercalary, hyaline. Conidia 2-3 µm diam, globose to narrowly ellipsoidal, hyaline, simple, smooth.
Teleomorph: Stromata absent. Ascomata to 300 µm, perithecioid, globose, not or slightly papillate, collapsing in a cupulate manner on drying, black, smooth, with or without a hyphal cortex, scattered, superficial on a subiculum composed of branched and anastomosed hyphae that is sometimes so dense as to form a membrane, hyaline to pale yellow brown and with numerous erect setae, superficial on adaxial surfaces of living leaves. Peridium composed of polygonal cells with yellow-brown walls. Interascal tissue composed of hyaline filaments. Asci 50-60 x 10-18 µm, clavate, thick-walled with two observable layers, J-, 8-spored, with a foot-shaped base. Ascospores 15-20 x 5-7 µm, 3- to 5-septate (mostly 3), narrowly ellipsoidal to ovoid, somewhat irregular, hyaline, smooth, not constricted at the septa.
Not formally assessed. Apparently reasonably widespread, but rarely recorded. An assessment would probably be of Least Concern.
Epiphytic on living leaves, mainly evergreens, including Buxus, Dryopteris aemula, Escallonia, Hedera, Ligustrum ovalifolium, Prunus laurocerasus, Rhododendron etc. Additional hosts in GB & I include Arundinaria, Acer macrophyllum, Eleagnus, Hydrangea, Mercurialis, Phillyrea and Rubus.
Throughout England (Cambs, West Cornwall, Durham, West & East Gloucs, Leics, Middlesex, Northants, West Suffolk, West Sussex, North East Yorks), E. & N. Ireland (Meath, Down, Sligo), W. Scotland (Argyll, Clyde Isles, North Ebudes), C. & N. Wales.
No firm data are available, but the fungus appears not to be parasitic and probably grows as a saprobe on leaf exudates.