We present a phylogenetic analysis using plastid (matK , rbcL) and nuclear (nrITS) DNA for diverse Euploca spp. (formerly Heliotropium section Orthostachys) from the worldwide distribution of a genus and including species encompassing the wide physiological and morphological diversity of the genus. Our results indicate that some remarkably complex features arose multiple times in parallel in Euploca , including attributes of its subsections under section Orthostachys , notably plants that, above ground, consist almost entirely of inflorescences. To elucidate in greater detail the distribution of C4 species in Euploca and Heliotropium s.s. we made > 800 δ 13C determinations, including some from the traditional genus Tournefortia. We greatly increase the number of proven C4 species in Euploca , but found none outside Euploca. Of the tested Euploca spp. c. 28% are C3 or intermediate in carbon fixation pathway. Our phylogenetic results indicate four parallel/convergent acquisitions of C4 photosynthesis or fewer origins with subsequent loss in some species. [ABSTRACT FROM AUTHOR]