Seed germination is the most important transitional event between early stages in the life cycle of spermatophytes and understanding it is crucial to understand plant adaptation and evolution. However, so far seed germination of phylogenetically closely related species has been poorly investigated. To test the hypothises that phylogenetically related plant species have similar seed ecophysiological traits thereby reflecting certain habitat conditions as a result of local adaptation, we studied seed dormancy and germination in seven Mediterranean species in the genus Romulea (Iridaceae). Both the across‐species model and the model accounting for shared evolutionary history showed that cool temperatures (≤ 15°C) were the main factor that promoted seed germination. The absence of embryo growth before radicle emergence is consistent with a prompt germination response at cool temperatures. The range of temperature conditions for germination became wider after a period of warm stratification, denoting a weak primary dormancy. Altogether these results indicate that the studied species exhibit a Mediterranean germination syndrome, but with species‐specific germination requirements clustered in a way that follows the phylogenetic relatedness among those species. In addition, species with heavier seeds from humid habitats showed a wider range of conditions for germination at dispersal time than species from dry habitats possessing lighter seeds. We conclude that while phylogenetically related species showed very similar germination requirements, there are subtle ecologically meaningful differences, confirming the onset of adaptation to local ecological factors mediated by species relatedness.

To facilitate biological study we define “Caribbean Islands” as a biogeographic region that includes the Antilles, the Bahamas, and islands bordering Central and South America separated from mainland areas by at least 20 meters of water depth. The advantages of this definition are that it captures nearly all islands with endemic species and with at least some Antillean-derived species, and still circumscribes a region of high biodiversity and biogeographic significance. We argue that Caribbean islands, in this expanded sense, are also cohesive from a conservation standpoint in that they share high human population densities and similar conservation threats. A disadvantage of this definition, strictly applied, is that it includes some islands (e.g., Trinidad) that have mostly mainland species. However, we propose that researchers can increase the stringency of the definition so that it is less inclusive, and make comparisons between different definitions as needed. We provide an updated checklist with standardized common English names for the 1,013 species of amphibians and reptiles occurring in the region, along with principles for constructing common names.