We describe a new family and genus of stoloniferous octocorals (Alcyonacea) and a new genus of Clavulariidae from material collected in South Africa in 2008. Arulidae, fam. nov., is characterised by polyps whose tentacles are fused proximally to form an expanded oral membrane, and sclerites of a type (‘table-radiates’) that has not been recorded previously in Octocorallia. One species, Arula petunia, gen. nov., sp. nov., is described, and the possible existence of congeners elsewhere in the Indo-Pacific is discussed. Inconstantia, gen. nov., is erected for three new species of Clavulariidae that have no or only weak anthocodial armature. I. pannucea, sp. nov., and I. procera, sp. nov., both have tall, cylindrical calyces, while I. exigua, sp. nov., has low, retractile calyces. Despite these morphological differences that would normally place them in different subfamilies, all three species are nearly identical genetically. We also describe Cornularia pabloi, sp. nov., a new species of Cornulariidae from South Africa, and discuss an unidentified species of Carijoa with an unusual colony growth form. A molecular phylogenetic analysis of 130 octocoral taxa, including 15 genera of stoloniferans, supports the distinctions of these new taxa from existing families and genera, and highlights the polyphyletic distribution of the taxa attributed to family Clavulariidae.