lobes: linear, elongate, up to 1.5 mm broad, but mostly around 1 mm, ± convex, weakly ascending at the tips, ciliate; cilia: marginal, white below and darkening above, up to 6 mm long upper surface: gray to very dark gray, usually minutely bullate, with stout cilia; soralia and isidia absent upper cortex: prosoplectenchymatous medulla: white, lowermost part often containing agglutinate hyphae that may appear like a cortex lower cortex: absent lower surface: white, shiny, agglutinated hyphae giving a false impression of a cortex, erhizinate Apothecia: abundant, very variable in size, short stipitate, up to 4 mm diam. with ciliate margins; disc: plane, black, often pruinose asci: subclavate to clavate, 8-spored ascospores: brown, l-septate, ellipsoid, Physcia-type, (15-) 16.5-19.7 (-22.5) x (6.5-) 7.5-9 (-9.5) Pycnidia: abundant and large, inserted, but distinctly protruding above lobe surface conidia: ellipsoid to bacilliform, 3-4 x 1 µm Spot tests: cortex K+ yellow, C-, KC-, P+ yellow; medulla K-, C-, KC-, P- Secondary metabolites: cortex with atranorin and chloroatranorin; medulla without any detected secondary products. Substrate and ecology: growing on rocks in sun-exposed, ± coastal habitats (see Esslinger and Bratt 1998) World and Sonoran distribution: only known on the Pacific Ocean side of Baja California and Baja California Sur. Notes: It is distinguished by its robust, orbicular thallus with elongate, discrete and ciliate lobes having abundant, ciliate apothecia. Its agglutinated medulla is also distinctive. In comparison with H. erinacea and H. namaquana, H. ciliatomarginata lacks zeorin and has more prominent pycnidia (up to 0.5 mm wide).