Thallus: crustose, effuse, 0.1-0.7 mm, surface: varying from white to creamy white, smooth, epruinose to slightly pruinose; soredia and isidia: not seen cortex: 10-50 µm thick Ascomata: numerous, circular in outline, sessile, 0.5-1.6 mm diam.; exciple: usually undulating; hymenium: 50-140 µm high; paraphysoids: sparsely branched, parallel, hyaline, c. 1 µm in diam. asci: clavate, 70-120 x 15 µm, 8-spored ascospores: fusiform, hyaline, 3-septate, 28-33 x 4-5 µm Spot tests: cortex K-, C+ red, KC+ red, P-; medulla K-, C-, KC-, P- Secondary metabolites: erythrin and lecanoric acid. Substrate and ecology: growing on trees and shrubs near the sea World distribution: only known from the Galapagos Islands outside of the Sonoran region Sonoran distribution: known from Baja California Sur (Todos Santos area) and Sonora. Notes: Dirina paradoxa subsp. approximata is similar to Roccellina conformis which also occurs on bark, but D. paradoxa is easily distinguished by its C+ red thallus. Dirina paradoxa includes two other subspecies, D. paradoxa subsp. hioramii in the Greater and Lesser Antilles, and Dirina paradoxa subsp. africana on the Canary Islands, the Atlantic coast of northern Africa and in Yemen and Socotra Island (Tehler 1983).