Usnea florida (L.) Weber ex Wigg.

    Thallus more or less erect, forming dense shrubby tufts, 5-8 cmm tall, blackened at base, main branches covered with minute papillae or spiny branches, isidia and soralia absent, medulla narrow but dense, secondary branches numerous, irregular, thinned out at tips, not constricted at base, yellow-greenish, grey-greenish. Apothecia numerous, typically arising at apices of main and major lateral branches, 0.5-1,5 cm diam., disc slightly concave at first then flat, whitish, white-ochre, fringed with marginal radiating cilia, to 0.2-0.5 mm long.  Ascospores broadly ellipsoid to ovoid, 8-11 x 6-7 µm. Photobiont: trebouxioid. Medulla: C-, K+ yellow, KC-, Pd+ red-orange ; apothecia disc : C-, K+ yellow, KC+ pink, Pd+ yellow. Not especially maritime, on twigs and branches in the canopy of broad-leaved trees, notably Quercus, and consequently  mainly visible on fallen branches, in ancient oceanic woodlands. This species is strongly declining in our prospection area. N.B. Usnea subfloridana is now considered as the same species, but generally is sterile, with soralia and isidia on terminal branches, and much more common, distributed in a more diverse habitat. In the mountains this species is replaced by a very similar species: Usnea intermedia who is P- on the apothecia discs and whose spores are smaller.