Croton awaensis (Euphorbiaceae), a new species of dragon’s blood tree from the Chocó-Andean region

Abstract We describe and illustrate Croton awaensis , a new species of dragon’s blood tree ( Croton sect. Cyclostigma ) with medicinal value distributed in the Chocó and Andean regions of Ecuador and Colombia. The species is a medium-sized tree occurring in humid lowland and lower montane forests, between 300 to 1500 m. It is characterized by a sublepidote indumentum, falciform stipules, 2 acropetiolar nectaries on the abaxial side of the petiole and 0–8 on the adaxial side, shortly pedicellate fruits, and bifid styles. Croton awaensis could be potentially confused with C. floccosus or C. coriaceus , which also grow in the northern Andean humid montane forests of Ecuador but at higher elevations. The new species grows sympatrically, sharing the same habitat and location, with C. chocoanus , another tree species that belongs to a different section in the genus ( C . sect. Luntia ). Phylogenetic analysis of DNA sequence data from the nuclear ribosomal ITS region supports the placement of the C. awaensis in C. sect. Cyclostigma and its closest relationship with a clade including several dragon’s blood species from northern South America and Mesoamerica. We present and illustrate a set of morphological characters to aid in the identification of specimens of C. awaensis using images from herbarium material and field observations. A preliminary conservation assessment indicates that the new species is likely endangered due to habitat loss resulting from agricultural expansion and the scarcity of protected areas within its distribution range.