Saurauia is a genus of flowering plants in the family Actinidiaceae, placed within the order Ericales. With approximately 300 species, it is by far the largest genus in its family and the only one whose natural range extends beyond Asia into the tropical and subtropical zones of Central and South America. Species are found across a wide swathe of the humid tropics, from the highlands of Mexico and Central America through Andean South America, and across southern and southeastern Asia.
The genus shares broad floral characteristics with its relatives Actinidia and Clematoclethra, the other two genera of Actinidiaceae, but can be distinguished by its gynoecium: Saurauia species consistently bear 3–5 carpels, a narrower range than the 3–30 or more seen in Actinidia and similar to the 4–5 of Clematoclethra. Notably, Saurauia is the only genus in the family whose members may be monoecious or functionally dioecious, a reproductive flexibility not seen in its relatives.
Monophyly of the genus is well supported by genetic evidence, cell biology, and micromorphological characters, as well as by phylogenetic analyses, though the precise evolutionary relationships among the three Actinidiaceae genera remain incompletely resolved.
Distribution
Saurauia is distributed across the tropics and subtropics of Asia (including southern and southeastern Asia) and the Americas (Central America and South America). It is the only genus in its family whose natural range extends beyond Asia.
Taxonomy Notes
Saurauia belongs to the family Actinidiaceae within the order Ericales. Monophyly of the genus is supported by genetic evidence, cell biology, micromorphological characters, and phylogenetic analysis, though its exact evolutionary relationships with the other two Actinidiaceae genera, Actinidia and Clematoclethra, remain unclear. It is the only Actinidiaceae genus with a native distribution outside Asia.
