A peer-reviewed open-access journal PhytoKeys 86: 9–42 (2017) Merging Acer sects. Rubra and Hyptiocarpa 9 doi: 10.3897/phytokeys.86.13532 RESEARCH ARTICLE http://phytokeys.pensoft.net Launched to accelerate biodiversity research On merging Acer sections Rubra and Hyptiocarpa: Molecular and morphological evidence AJ Harris1, Yousheng Chen2, Richard T. Olsen3, Sue Lutz1, Jun Wen1 1 Smithsonian Institution, Department of Botany, MRC 166, Washington, D.C. 20013-7012 USA 2 Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093 China 3 United States National Arboretum, 3501 New York Avenue, NE, Washington, D.C. 20002-1958 USA Corresponding author: AJ Harris (
[email protected]) Academic editor: P. Acevedo-Rodríguez | Received 3 May 2017 | Accepted 22 August 2017 | Published 18 September 2017 Citation: Harris AJ, Chen Y, Olsen RT, Lutz S, Wen J (2017) On merging Acer sections Rubra and Hyptiocarpa: Molecular and morphological evidence. PhytoKeys 86: 9–42. https://doi.org/10.3897/phytokeys.86.13532 Abstract In this study, we expanded Acer sect. Rubra Pax to include A. sect. Hyptiocarpa Fang. Traditionally, section Rubra comprises two iconic species, Acer rubrum Linnaeus (red maple) and A. saccharinum Linnaeus (sil- ver maple), of eastern North American forests as well as the rare Japanese montane species, A. pycnanthum K. Koch. Section Hyptiocarpa consists of A. laurinum Hasskarl and A. pinnatinervium Merrill, which occur in subtropical and tropical regions of southwestern China to southeast Asia. Here, we confirm prior phylogenetic results showing the close relationship between sects. Rubra and Hyptiocarpa, and we use scanning electron microscopy to demonstrate that leaves of species within these sections have similar arrangements of cuticular waxes, which account for the silvery color of their abaxial surfaces.