EVOLUTION OF PEPEROMIA (PIPERACEAE) IN THE JUAN FERNANDEZ ISLANDS, CHILE

Four species of Peperomia (Piperaceae) occur in the Juan Fernandez Islands, Chile: P. berteroana, P. margaritifera, P. skottsbergii, and P. fernandeziana. The last species is found also in continental Chile, whereas the other three are endemic to the archipelago. Peperomia margaritifera is found only on the older island of Masatierra, whereas P. skottsbergii is confined to the younger island of Masafuera, and P. berteroana occurs on both islands. Phenetic analyses of mainland taxa suggest that P. fernandeziana belongs to subg. Sphaerocarpidium whereas the endemic taxa form their own subg. Tildenidium connecting to subg. Tildenia. Cladistic analyses indicate that P. margaritifera is the most primitive species in the archipelago and that P. berteroana is the most derived, especially patristically. Chromosomally, the four species are all n = 22, which may be tetraploid on a base of x = 11. Sulfated flavones occur only in P. berteroana and P. skottsbergii, which are otherwise unknown for the family. Dispersal of propagules to the islands from the continent and between islands is believed to have been accomplished by birds.