Soyauxii

Soyauxii is a small genus of flowering plants in the family Rubiaceae, native to the tropical forests of Central Africa and Madagascar. The genus was first described in the early 20th century by the French botanist Jean‑Luc Soyaux, after whom it is named. It comprises three recognized species: Soyauxii africana, Soyauxii madagascariensis, and Soyauxii tenuiflora. All members are evergreen shrubs or small trees, reaching heights of 2 to 8 metres, with opposite, leathery leaves and white to pale yellow inflorescences arranged in terminal panicles. The flowers are hermaphroditic, bearing a tubular corolla that attracts a variety of pollinators, primarily bees and hummingbirds. Fruit development yields small, indehiscent capsules containing one to two seeds.

The genus occupies low‑land rainforest understories, thriving in well‑drained, acidic soils with high humidity. Though not of major economic importance, certain local communities utilize the wood of Soyauxii africana for light construction and the leaves of S. tenuiflora in traditional medicinal preparations for treating skin irritations. Conservation assessments indicate that habitat loss due to logging and agricultural expansion places two of the species at risk of becoming threatened, prompting inclusion in regional biodiversity action plans. Ongoing taxonomic research, supported by molecular phylogenetics, seeks to clarify the genus’s relationship to other Rubiaceae lineages and to identify possible cryptic species within its range.