Graphina ruiziana (Fée) Müll. Arg.

    Thallus crustose, continuous, smooth to more or less rough, sometimes evanescent, whitish, grey-whitish, pale grey-greenish. Apothecia lirelliform, usually numerous, short and stocky, 0.5-2.5 x 0.3-0.5 mm, markedly elevated, and seemingly lying on the thallus, simple, not branched, straight, slightly curved or somewhat flexuose, black and slightly shining, disc thin and slit-like, black but occasionally white pruinose as the margin (apothecia look like carbonized coffee-bean or like a closed mouth with thick lips). Asci: 8-spored. Ascospores colourless, muriform (approximately 30 cells and 7 transverse septa), I+ brown-purplish to violet-purple, mature ascospores, 30-45 x 15-18 µm with 1 perispore, 1-2 µm - in water. Pycnidia occasional, visible as black dots. Photobiont: Trentepohlia. Chemical spot tests negative. Rare tropical thermophilic species growing on smooth bark of deciduous trees, notably Ulex, more seldom Quercus, in very humid hyperoceanic woodlands. N.B. If the apothecia are brown-blackish and slightly incrusted in bare wood, see Gloniopsis praelonga that is a not lichenized (thallus absent) ascomycota and with rather similar ascospores but I-. This iodine reaction is physical, not chemical and not always reliable. Also, in case of absent thallus, see Hysterium pulicare (ascomycota not lichenized) of which the fruiting bodies (hysteriotheca) are very similar, but with several longitudinal furrows and with fili-fusiform ascospores 3-6-septate, dark brown cells towards the center and pale at apices. See also Hysterium angustatum of which ascospores are evenly brown and 3-septate. Graphina pauciloculata is similar but in reduction, with smaller ascospores. Since it often is associated to Graphis ruiziana, one can hypothesize parasitic interrelations between the two species. N.B. On the field, not to be connfused with Graphis elegans of which the lirellae have several furrows and the thallus is K+ red and Pd+ yellow-orange.*