Description contributed by Graham Kinsey (CABI).
Anamorph: Sporonema sp., sometimes referred to as Zythia fragariae. Conidiomata 130-350 µm diam, pycnidial, cavity sometimes convolute, yellowish brown to black, ostiolate, papillate, at first immersed in the host tissue, later erumpent. Conidiophores 10-15(-25) µm long, cylindrical, septate, hyaline, occasionally branched, arising from the cells lining the inner surface of the pycnidial cavity. Conidiogenous cells cylindrical to elongate flask-shaped, enteroblastic, phialidic. Conidia 4-7 x 1-2 µm, cylindrical with rounded ends, simple, 2-guttulate.
Teleomorph: stromata absent. Ascomata 220-300 µm diam, papillate or with a neck to 400 x 50-90 µm. Peridium 25-35 µm thick, composed of 4-6 layers of cells. Interascal tissue absent. Asci 20-35 x 3.5-8 µm, 8-spored. Ascospores 6.5-13 x 1.5-2.5 µm, cylindrical to narrowly ellipsoidal, septum dividing the length 1:1 to 2:1, larger cell uppermost in the ascus, lower cell often more tapered, without appendages, each cell usually containing 2 small guttules.
Frequently referred to a Gnomoniopsis comari (syn. Gnomonia comari), but according to Sogonov et al. (2008) this is a morphologically similar but phylogenetically distinct species that is apparently restricted to Comarum palustre (Rosaceae).
Similar fungi on dead leaves of Potentilla are probably referable to G. tormentillae.
On dead leaves and inflorescences of Fragaria and Geum.
From England (including Berks, West Gloucs, Herts, East & West Kent, East Sussex), N Ireland, Scotland (Ayrshire, Outer Hebrides, Kintyre) and S Wales.
A necrotrophic pathogen. Infected calyces and receptacles turn dark brown and wither (stem end rot and fruit rot), longitudinally elongate necrotic spots form on stems, pedicels and petioles, infected leaves turn dark brown and wither. According to Morocko & Fatehi (2007), this species is a relatively weak pathogen, with the morphologically similar and more virulent Gnomonia fragariae causing similar disease symptoms.