Thallus: fruticose, shrubby to rarely subpendulous, up to 7(-15) cm long branching: moderately branched from a narrow holdfast branches: solid, lanceolate, plane or +canaliculate, surface smooth in young branches, longitudinally to irregularly ridged by protruding cartilaginous tissues in older branches, up to 3(-5) mm wide surface: greenish gray to greenish yellow, smooth, shiny, without soredia pseudocyphellae: linear, laminal or rarely marginal, flat or more commonly depressed cortex: thin; chondroid strands: continuous, smooth, never forming bundles of hyphae Apothecia: commonly laminal on one side of blade, the other side have no or few apothecia, up to 1.5 mm in diam. disc: flat to +convex, without pruina, without white margin; margin: concolorous with the thallus, entire, without pseudocyphellae asci: elongate-clavate, 8-spored ascospores: hyaline, 1-septate, broadly fusiform, 12-16 x 4-6 µm Pycnidia: not observed Spot tests: cortex K-, C-, KC+ yellow, P-; medulla K-, C-, KC-, P- Secondary metabolites: cortex with usnic acid (major); medulla: none detected. Substrate and ecology: on bark World distribution: widely distributed in tropical and cool temperate regions in the Southern Hemisphere as well as southern North America, Central America, southeast Asia (Indonesia), Australasia, and East Africa Sonoran distribution: rare in Baja California Sur and Sonora. Notes: Ramalina celastri is very rare in the Sonoran area, but is more common in central and southern Mexico (Chiapas, Hidalgo, Nuevo Leon, Puebla) and Texas. Differences between R. celastri and R. leptocarpha are given below the description of the latter species.