Geniostoma is a genus of around 49 species of flowering plants in the family Loganiaceae. They are shrubs or small trees, with inflorescences borne in the axils of the simple, petiolate, oppositely-arranged leaves. The flowers are arranged in cymes, and each is pentamerous.

The name Geniostoma derives from the Greek words γένειον (geneion; "beard") and στόμα (stoma; "mouth"), referring to the hairs in the corolla tube of some species. The genus is widely distributed across the Pacific Ocean from Japan, Malesia to Australia in the west, and east to the Tuamotu Archipelago; one species is also found on the Mascarene Islands.

The Hawaiian endemic genus Labordia is included in Geniostoma by Plants of the World Online and other authors. The Hawaiian species are commonly known as labordias or as Kamakahala in Hawaiian. These two genera have been grouped together in the family "Geniostomaceae", but are considered by the Angiosperm Phylogeny Group to be part of a wider Loganiaceae.

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