A rare Macaronesian species with only two records from oceanic woods at Covelly, North Devon and Luing, Argyll. Very similar to Porina borreri and can only be distinguished by the fusiform ascospores which are narrower and longer (length to breadth ratio of 12 to 18) than those of P. borreri, which are distinctly clavate with a length to breadth ratio of between 6 – 8. Potentially overlooked in other oceanic woods.
Like Porina borreri, but with narrower and longer ascospores 30–55 × 2.5–3.5 (–4) µm, with a length to breadth ratio of between 12 to 18.
There are no obvious field features separating this species from Porina borreri but, the spores are distinct, with the narrowly fusiform spores of P. leptospora having a length to breadth ratio of well over 10. Porina borreri has distinctly clavate spores with a length to breadth ratio of less than 10 (typically between 6 – 8).
On flushed bark of Hazel, Ivy and Holly in oceanic woodlands.

Rarely seen, N. Devon, S.W. Scotland, S.W. Ireland (Killarney), likely overlooked but still rare.
Recorded form only two widely separated lichen rich Atlantic woodlands, but potentially overlooked in others.
Britain: Near Threatened
Orange, A., Cannon, P., Malíček, J., Sanderson, N., Coppins, B. & Simkin, J. (2021). Ostropales: Porinaceae, including the genus Porina. Revisions of British and Irish Lichens 4: 1-12.
Text by N A Sanderson, based Orange et al (2021)