Stauffer, F.W., J. Eychenne, N. Ortega & H. Balslev (2019). Structural biology and evolution in the monotypic Amazonian palm Wendlandiella (Arecoideae: Chamaedoreeae) Candollea 74: 15–30. In English, English abstract. DOI: http://dx.doi.org/10.15553/c2019v741a3The structural biology is here, for the first time, described in the Amazonian palm genus Wendlandiella Dammer, a poorly known and monotypic member of the early divergent tribe Chamaedoreeae Drude (Arecoideae). Wendlandiella gracilis Dammer includes three varieties: var. gracilis, var. polyclada (Burret) A.J. Hend., and var. simplicifrons (Burret) A.J. Hend. In contrast to the overwhelmingly monoecious condition in this subfamily, Wendlandiella together with the species-rich genus Chamaedorea Willd., presents a dioecious reproductive syndrome. The terrestrial root system, the leaves and the stems of Wendlandiella display a relatively simple architecture and vegetative multiplication observed in wild populations may be regarded as an important mechanism of reproduction. Flowers in Wendlandiella are arranged in a complex floral cluster known as acervulus, clearly deviating from the floral triad characterizing most other members of the subfamily. Our study describes the structure of the acervulus in inflorescences of both sexes. The lack of a nectariferous epithelium in the gynoecium and the pistillode suggests that Wendlandiella is wind pollinated, which is a rare pollination mechanism in palms. Wendlandiella is proposed as an interesting model to test the different evolutionary pathways to dioecy in palms.Received: September 14, 2018. Accepted: January 26, 2019. First published online: March 28, 2019.