Intercontinental dispersal: The origin of the widespread South American plant species Gilia laciniata (Polemoniaceae) from a rare California and Oregon coastal endemic

Although separated by 7000-km, Gilia millefoliata, a rare annual plant from California and Oregon coastal dunes and G. valdiviensis, a rare Chilean coastal endemic are morphologically and ecologically quite similar. Their disjunct distribution was proposed to result from recent, bird-mediated, intercontinental long-distance dispersal. Both species are morphologically similar to the abundant and ecologically diverse South American taxon G. laciniata. The relationship among these three taxa was investigated using DNA sequence from the nuclear ribosomal (ITS) and chloroplast trnL regions, as well as isozyme and morphological variation to determine the roles of long-distance dispersal and ecological adaptation in the evolution of the group. These data suggest that a G. millefoliata-like ancestor underwent long-distance dispersal to South America, and there gave rise to the narrow endemic G. valdiviensis and the widespread G. laciniata.