Lichen: Punctelia borreri
Name: Punctelia borreri (Sm.) Krog (1982)
Old name: Parmelia borreri
Pronunciation: no – will be posted later
Conservation Evaluation: Least Concern
Description: The thallus is a gentle grey colour often with hints of yellow and a little brown at the ends of some of the lobes. The edges are tightly adpressed but the central area may become free of the substrate. The lobes vary considerably in size (2 to 30mm) and are undulating with ascending margins; the margin may be indented. In a suitable environment a mature thallus may reach a diameter of 20cm. Pseudocyphellae are usually abundant, are white in colour and under a hand lens may be seen to rise to a point (punctiform). The soredia tend to be black. Apothecia are rare; diameter is up to 6mm and the discs red-brown. Pycnidia are also present across the surface of the lobes. The underside is black and is packed tightly with pale tipped rhizines; the rhizines fall short of reaching the edge of the lobes.
Chemical Tests: Cortex K+ yellow. Medulla C+ pink. K-, KC+ pink. Pd-, UV-.
Nature Notes: Likes deciduous trees in open well lit nutrient rich areas such as near farms, in small towns and orchards. Often found in the company of Flavoparmelia soredians, Physconia distorta, Physconia grisea and Candelaria concolor. Sometimes found on coastal and seashore rocks.
Similar species: Punctelia subrudecta (does not have a black underside). If C- then it’s P. reddenda. Laminal soralia and brownish/pruinose edges with a C+ reaction would make it P. jeckeri (was Punctelia ulophylla).
Vice county distribution map: See map.
Link: Map this species on the Lichen Survey
Other species recorded in Ireland:
- Punctelia reddenda (Stirt.) Krog
- Punctelia subrudecta (Nyl.) Krog 
- Punctelia ulophylla (Ach.) Van Herk & Aptroot
Text and images © Paul Whelan, 2010.