Bactrospora homalotropa (Nyl.) Egea & Torrente

   Thallus thin, smooth, greyish-white, whitish, white-glaucous, sometimes with orange spots in the wounds or scratches (Trentepohlia), no prothallus except in case of contact with other species. Apothecia numerous, scattered all over thallus, 0.2-0.6 mm diam., discs concave to flat, black, thick margin regular and continuous at first and then quickly torn and irregular, black. Asci with 8 parallel very lengthy ascospores (cylindri acicular). Ascospores up to 50-septate, 110-140 x 3-5 µm; display the specific property of self-fragmentation in small rectangular or square fragments immediatly after being expelled from asci (in section, optical microscopy). Photobiont : Trentepohlia. Chemical spot tests negative. Rare, on smooth bark of trunks in humid, sheltered oceanic woodlands in a hyperoceanic Graphidion community together with other corticolous species and notably Thelotrema petractoides.*