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 according to literature; (10) 12-15 (17) x 5-8 (9) µm according to our measurements. 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, but very rare on conifers, but see: Teloschistes chrysophthalmus forme sur conifères and even rarer on rocks, but see: Teloschistes chrysophthalmus forme saxicole. completely anecdotal on artificial substrates, but see: Teloschistes chrysophthalmus forme sur substrats artificiels. 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, Xanthoria parietina forme ramicole, Physcia tenella forme ramicole, etc. It is very sensitive to the quality of the air, except for ammonia, of which it is tolerant (and even of which it seems to "benefit" for its growth).

N.B. Species with "eclipse" and often ephemeral which appears quickly in its stations then disappears just as quickly without apparent reasons ...