Synonyms: Aracium laevigatum (homotypic); Crepis laevigata (homotypic); Crepis papuana (heterotypic); Ixeridium oldhamii (heterotypic); Ixeris laevigata (homotypic); Ixeris laevigata lanceolata; Ixeris laevigata oldhamii; Ixeris laevigata var. laevigata; Ixeris laevigata var. lanceolata (heterotypic); Ixeris laevigata var. oldhamii (heterotypic); Ixeris lamii (homotypic); Ixeris oldhamii (heterotypic); Ixeris papuana (heterotypic); Ixeris prolixa (heterotypic); Ixeris stenophylla (heterotypic); Ixeris umbellata (heterotypic); Lactuca dentata lanceolata; Lactuca dentata var. lanceolata (heterotypic); Lactuca laevigata (heterotypic); Lactuca laevigata excisodentata; Lactuca laevigata laevigata; Lactuca laevigata pygmaea; Lactuca laevigata var. excisodentata (heterotypic); Lactuca laevigata var. lamii (heterotypic); Lactuca lamii (homotypic); Lactuca luzonica (heterotypic); Lactuca oldhamii (heterotypic); Lactuca papuana (heterotypic); Lactuca prolixa (heterotypic); Lactuca stenophylla (heterotypic); Lactuca thunbergiana; Lactuca umbellata (heterotypic); Prenanthes laevigata (homotypic)