Porpidia superba
≡Lecidea superba Körb., Syst. Lich. Germ.: 248 (1855).
Description : Thallus thick, verrucose to verrucose-uneven, white, scabrid, esorediate, with ±continuous or dispersed bullate areolae sometimes constricted at base. Medulla I−. Prothallus black, between areolae or inconspicuous. Apothecia 0.5–2 mm diam., common, scattered among areolae, immersed at margins of areolae at first, becoming sessile and ±constricted at base, disc dark-brown, rarely thinly white-pruinose, flat or convex, exciple thick, black. Epithecium 20 μm thick, yellowish to orange-brown. Hymenium 110–140 μm high. Ascospores 17–25(–33) × 8–12(–14) μm.
Chemistry : Medulla: K+ yellow or −, C−, KC−, Pd+ orange; containing stictic acid.
S: Known also from Great Britain, Europe, Scandinavia, North America, and the Himalaya (Hertel 1967, 1977b; Gowan 1989b; Galloway & Coppins 1992b; Gowan & Ahti 1993; Nimis 1993; Santesson 1993; Esslinger & Egan 1995; Scholz 2000; Nimis & Martellos 2003; Santesson et al. 2004; Fryday 2005).
Bipolar
Illustrations : Hertel (1977a: 223 – as Huilia superba); Gowan (1989b: 52, fig. 56); Foucard (1990: pl. 266).
Porpidia superba is characterised by: the saxicolous habit; the scabrid, white upper surface; the often dispersed, ±bullate areolae; the brown apothecial discs contrasting with the black margin; the orange-brown epithecium; and a chemistry containing stictic acid.
