Parmotrema cetratum
≡Parmelia cetrata Ach., Syn. meth. lich.: 198 (1814).
≡Rimelia cetrata (Ach.) Hale & Fletcher, Bryologist 93 (1): 26 (1990).
Description : Flora (1985: 356–357).
Chemistry : Cortex K+ yellow; medulla K+ yellow→red, C−, KC+ red, Pd+ orange; containing atranorin, chloroatranorin, salazinic acid (major) and consalazinic acid (minor).
N: S: Common on coastal rocks. Pantemperate, pansubtropical, especially common in SE United States and South Africa (Hale & Fletcher 1990; Becker 2002). Known also from Arizona and Mexico, Japan, Hawai'I, and Australia (Moon et al. 2001; Nash & Elix 2002h; Kurokawa 2003; McCarthy 2003c, 2006).
Cosmopolitan
Illustrations : Moon et al. (2001: 324, fig. 2); Brodo et al. (2001: 642, pl. 784); Kantvilas et al. (2002: 154).
Parmotrema cetratum is characterised by: the saxicolous habit; the smooth cortex; and the absence of soredia.