Thelotremataceae Thelotrema lepadinum Growth type crustose Chemical results negative Usually on sheltered, smooth-barked, deciduous trees, occasionally on acidic rocks. NIEC 'Old woodland' indicator species Variable. Greyish-cream thallus is thick or thin, smooth or uneven with numerous barnacle-like raised apothecia with large central openings. Discs usually visible, +/- white-pruinose. Apothecia are larger, more open and ulcerose in moist, shady sites. Host to various lichenicolous fungi including Skyttea nitschkei, Opegrapha thelotrematis and Arthonia thelotrematis

Thelotrema lepadinum
Wessex Lichen Group meeting, New Forest, Hants. December 2012