revision on the world level is made for Relicina, a generic segregate of Parmelia characterized by having bulbate cilia on the lobe margins and by producing usnic acid in the cortex. Of the 24 species presently known, 19 occur in the Old World tropics, with the greatest concentration in the lowland dipterocarp forests, 3 are endemic to the New World tropics, and 2 occur in both the New and Old World outside of Africa. The most important taxonomic characters are type of rhizine (simple or branched), presence of coronate apothecia, isidia, and chemistry. The major chemical constituents are echinocarpic acid, fumarprotocetraric acid, and protocetraric acid. The genus is considered to be of fairly recent origin but rather conservative in terms of morphological and chemical evolution. Four new species, R. amphithrix, R. incongrua, R. precircumnodata, and R. subconnivens, are described and one new combination, R. relicinula (Müll. Arg.) Hale, is made.