A systematic revision of <i>Croton</i> section <i>Cyclostigma</i> (Euphorbiaceae) in Ecuador
Section Cyclostigma, one of 40 sections in the large (>1,000 spp.) genus Croton, contains approximately 50 species, which are primarily distributed in the Neotropics. This section of Croton is referred to as the “sangre de drago” (dragons blood) group due to the presence of red latex in many species that is used for the treatment of numerous ailments. This study reviewed all 43 Neotropical species from section Cyclostigma, as well as other species that showed affinities with the section, to identify and resolve Ecuadorian species of section Cyclostigma. Trichome morphology, seed surface morphology, and foliar gland position were all shown to be particularly useful in making taxonomic decisions in this group. Twelve species from this section are now recognized as indigenous to Ecuador, including two endemic species and one new species presently described. A key to the twelve species found in Ecuador along with descriptions, photographic illustrations and distribution maps are provided. At the end of each species description, there is a discussion of useful field characters, and a list of local names and medicinal uses. Eight new synonymizations are proposed, and revised list of species in section Cyclostigma is given in appendix A.