Parmeliaceae Hypotrachyna britannica Identification is uncertain Growth type foliose Chemical results: Cortex K+ yellow. Medulla K-, C+ red, KC+ red, P-, UV- Often coastal on sheltered, well-lit siliceous rocks. Specimens on trees (including these shown here) are probably Hypotrachyna afrorevoluta. Whitish-grey or pale bluish-grey lobes, the tips often brownish and +/- ascending. Under surfaces dark-brown or black with paler margins, rhizines simple or tufted, marginal cilia rare. Medulla white. Sub-marginal bluish-black soredia develop from pustules on lobes. Apothecia are absent.

Hypotrachyna
On Birch. Holton Lee, Dorset. October 2012