Teloschistes chrysophthalmus (L.) Th. Fr.
Thallus fruticose, forming tufts, more or less spherical, 1-5 cm diam., lobes flat to slightly convex, 1-2.5 mm wide, radiating from a central point, more or less branched, margin with irregular and abundant spinules. Upper surface yellow to golden orange, lower surface pale yellow tinged-greyish. Apothecia numerous, marginal or near apices, discs to 5 mm diam., with abundant marginal cilia (eye-like, explaining its name: golden eye), discs orange, cilia yellow-orange. Ascopsores ellipsoid, polarilocular, 10-15 x 5-8 µm. Photobiont: Trebouxioid. K+ purple. Magnificent species easy to identify and impossible to mistake with another species. In our prospection area, typically found on Prunus spinosa in the aerohaline zone, notably on twigs already covered with other lichens. Also found on other ornmental bushes or trees notably in gardens near the seashore. This species is much rarer inland but seems to increase in the Finistere where it is common and abundant in some coastal areas, to the difference of Great-Britain and ireland where it is under decline and extremely rare. N.B. This species is often found in association with Physcia leptalea and seems rather tolerant to air ammonium.*