A taxonomic revision of Geniostoma subg. Geniostoma is presented. The relationship between Labordia and Geniostoma is discussed; Labordia being regarded as a subgenus of Geniostoma. General chapters on morphology, anatomy, seed dispersal, chromosome numbers, inter- and intraspecific relationships, geography, and evolution precede the systematic treatment. Two sections are recognised in the subgenus Geniostoma. Section Macrostipulare is described as new. Two sections (sect. Labordia and sect. Darbolia) are recognised in the subgenus Labordia. Section Rabdolia is reduced to the synonymy of section Labordia. Twenty-three species of Geniostoma subgenus Geniostoma are recognised, of which five are described for the first time. The new species are G. grandifolium, G. leenhoutsii, G. mooreanum, G. trichostylum, and G. umbellatum. Fourteen varieties of G. rupestre are recognised, of which var. rouffaeranum and var. solomonense are described as new. A general key to the species plus two regional keys, one for Papuasia and one for New Caledonia, and keys to the varieties are provided. All recognised taxa are provided with full descriptions, distribution, ecological and other relevant notes. Most species and varieties are illustrated. A full enumeration of collections examined is provided.