Pertusaria pseudocorallina (Lilj.) Arnold morpho microstictica

    Thallus crustose, tightly appressed to the substratum, 1-2 mm thick, edges not lobate, crazed to areolate with sterile and angular areoles, more or less flat, slightly verrucose and only rough, 0.5-1.5 mm across, minute isidia, 0.1-0.3 mm tall and diam., globose or constricted at base and tip rounded, scattered over limited sections or all over the thallus, in limited number and seldom heap-forming, brown blackish, blackish, overall thallus colour pale grey, white greyish without clear ochre-pink tinge, prothallus often visible, more or less delimited, greyish. Apothecia rare, immersed in fertiles warts, convex and regular, 2-3 mm diam., punctiform, 2-5 apothecia per fertile wart, blackish, knocked at the top. Ascii 2-spored.  Ascospores ellipsoid, thick walls, 120-200 x 50-80 µm. Photobiont: Chlorococcoid. Thallus: C-, K+ yellow > red, KC+ yellow > red, Pd+ yellow > orange (slow reaction). This morph of Pertusaria pseudocorallina is not rare on shaded and moist siliceous rocks in the aerohaline zone. Differs from the canonical type of Pertusaria pseudocorallina by its fertile warts and the minute globose isidia, not club-shaped and black, and the less verrucose and more areolate aspect of the grey thallus, devoid of distinct ochre-pink tinge.

N.B. Intermediate specimen between this morph and both the sterile type and the fertile type Pertusaria pseudocorallina fertile form may be found and this suggest to restrict these specimen to the rank of a distinct morph.

N.B. In some taxa isidia are absent and in the field they look similar to Roccellographa (Peterjamesia) circumscripta but the latter is K-.