Similar to Phaeographis inusta, but with a yellow-green-olive, waxy thallus and flat but raised apothecia, with clear white powdery margins. The apothecia are typically arranged in parallel and less branched and stellate than P. inusta. Resticted to the far south west where in can be found on both old trees and young trees in humid locations.
Thallus thin, in patches or mosaics, yellow-brown to dark olive-green, waxy or glossy, smooth or sparingly cracked, occasionally white-pruinose in parts. Apothecia black- brown, ± emergent, broad, flat, elongate, flexuose, unbranched, branched or stellate; thalline margin conspicuous, white-powdery, mainly comprising of large crystals; true exciple entire, dark brown, lateral walls 25–35 μm thick, broadening to ca 60 μm above; disc 0.15–0.5 mm wide, broadly expanded, ± finely pruinose; hymenium 90–120 μm tall. Ascospores (20–) 24–35 × 7–9 μm, (3-)5- septate. Conidia 8–10 × ca 4.5 μm, ellipsoidal, straight or slightly curved. No lichen products detected by TLC.
Recognised by the yellow-green-olive, waxy thallus and flat but raised apothecia, with clear white powdery margins
On ± shaded, smooth bark of deciduous trees, especially saplings and young trees, in humid situations in old woods, rare on wayside trees
Rare to locally occasional, S.W. England, W. Wales, S.W. Ireland.
Assessed as Near Threatened, but although rather restricted geographical in England, it does readily colonise young trees in sheltered locations, and may be spreading to an extent locally, however it is very rare in Wales. Quite widepsread and colonising young Beech plantations near the south coast of Ireland.
Britian: Near Thretened, International Responsibility species
Wales: Vulnerable
Aptroot, A., Weerakoon, G., Cannon, P., Coppins, B., Sanderson, N. & Simkin, J. (2023). Ostropales: Graphidaceae, including the genera Allographa, Clandestinotrema, Crutarndina, Diploschistes, Fissurina, Graphis, Leucodecton, Phaeographis, Schizotrema, Thelotrema and Topeliopsis. Revisions of British and Irish Lichens 36: 1-23.
Text by Neil A Sanderson based on Aptroot et al (2023)