A New Combination in Euploca (Heliotropiaceae) Endemic to the Galapagos Archipelago, Ecuador

Abstract

The genus Euploca (Heliotropiaceae) was proposed by Nuttall (1836) and in its current circumscription, following Diane et al. (2003), also encompasses all the species in Heliotropium section Orthostachys, as well as the species belonging to the genera Hilgeria Förther and Schleidenia Endl. On the basis of Diane et al. (2016), Euploca includes about 100 cosmopolitan species. They grow especially in dry zones with centers of taxonomic diversification in Mexico and South America, the later in which it is represented by 33 species. The majority of these (28 spp.) are endemics, corresponding to approximately 85% of all the species, various of them occurring in the Southern Cone (Southern Brazil, Uruguay, Argentina, Chile, and Bolivia). Only one species occurs in Chile (E. procumbens (Mill.) Diane & Hilger), and two species are reported from Ecuador, one of them endemic to the Galapagos Archipelago. Euploca species, vegetatively, are herbs, subshrubs, and rarely shrubs. The leaves are alternate to pseudo-opposite, rarely pseudoterminate, linear to broadly ovate or obovate. Inflorescences are 1-pluribranched, rarely ebracteose (encompassing a small group of species predominantly found in South America, e.g., E. barbata (DC.) J. I. M. Melo & Semir, a species restricted to the Caatinga vegetation, in Northeastern Brazil), many-flowered or presenting single flowers as in E. lagoensis (Warm.) Diane & Hilger, a species largely distributed in the Neotropics, and E. parciflora (Mart.) J. I. M. Melo & Semir, an endemic species from Brazil (Caatinga and Cerrado). Fruit are dry, separating into four 1-seeded mericarpids (Diane et al., 2016) adapted to hydrochory (water-dispersed as probably in E. paradoxa