This paper is a compilation and analysis of vascular plants that have been reported present on the eight atolls of the independent nation of Tuvalu in the Central Pacific. It is based on field inventories conducted by the author and collaborators between 1991 and 2016 plus available published and unpublished records of vascular plant collections and observations made since the late 1800s. The indigenous vegetation and flora of Tuvalu are highly disturbed and the flora is now numerically dominated by introduced exotic species. This has been the result of a long post–European contact and British colonial heritage, including over a century of planting monocultural coconut plantations; extensive habitat destruction, excavation and conversion of much of the best cultivable land from “borrow pits” to build airstrips during World War II; rapid population growth, including the migration from outer atolls to, and the expansion of, the main settlement and government center on Funafuti Atoll; and increased shipping and air services and agricultural development projects that have facilitated the introduction of new plants.
The total number of vascular plant species that have been recorded at some time on Tuvalu, including all indigenous and introduced species, is about 362 species or distinct varieties, of which only about 59 (16%) are possibly indigenous. The remaining 303 species (83% of the flora) are non-indigenous species that have been introduced by humans, some of which may have been at one time or another early aboriginal introductions. There are no endemic species that are unique to Tuvalu, with almost all of the indigenous plants being widespread, easily-dispersed coastal species that have the ability to cope successfully in the harsh atoll environment. The low number of indigenous species is an indication of the lack of habitat diversity on atolls compared with larger high islands, the difficulty of cross-ocean dispersal by plants, and the difficulty of long-term survival in the harsh atoll environment, which is dominated by poor soils, high salinity and physiological drought. Despite the degradation, the 362 or so plant species that still survive in Tuvalu are the only plants that the inhabitants have to satisfy many of their most important cultural, economic and environmental needs and to give them resilience against climate and global change.