Ocellomma picconianum found new to Britain



Ocellomma picconianum is an internationally scarce Mediterranean – Southern Atlantic lichen of dry bark on trees, which is typically found on Holm Oak in humid Mediterranean woodlands (Nimis, 2023). The nearest record before 2023 was in an old riverine woodland in the Landes, Gironde on the Atlantic Coast of France (Roux, et coll., 2020). Remarkably in 2023, David Hill, Juliet Bailey and Jo Corke, found this lichen on shaded dry bark on an old Willow in a hedge on the Severn plain, within the Elmore Court rewilding, in Gloucestershire. Superficially it resembled Lecanactis abietina, but the C+ red pruina of the pycnidia of that species were missing and the spores were too small, but it did appear to be a Arthoniales species. The combination white pruinose apothecia and the black pycnidia, however were distinctive and suggested something new. The surprising answer was provided by  Damien Ertz. More information can be found here: https://britishlichensociety.org.uk/resources/species-accounts/ocellomma-picconianum