DOI: 10.5061/dryad.n26nd
title: Data from: On merging Acer sections Rubra and Hyptiocarpa: molecular and morphological evidence

description: 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
 (silver 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. We describe that the
 sections also share labile sex expression; inflorescences that range from
 compound racemose thyrses, to racemes or umbels and that may have
 undergone evolutionary reduction; and several features of their fruits,
 such as seed locules without keels, basal portion of wings straight, acute
 attachment angle between mericarps, and production of some mericarps that
 are seedless and partially developed at maturity. Our expansion of sect.
 Rubra to include sect. Hyptiocarpa better elucidates the biogeographic and
 evolutionary history of these species. Additionally, we show that A.
 laurinum and A. pinnatinervium have intergrading morphology and are
 probably synonymous, but we note that further studies are required to
 conclude their taxonomic status.
description: DNA Matrices and
 Phylogenetic TreesAligned DNA sequences of
 Acer comprising datasets of internal transcribed spacer (ITS) and the
 cpDNA spacer, psbM-trnD, as well as a concatenated dataset. Also includes
 summary trees resulting from Bayesian, maximum likelihood, and neighbor
 joining analyses of these datasets. Tree files contain support
 values.Leaf Surface
 MicrographsScanning electron
 micrographs of leaf surfaces of Acer laurinum, A. pycnanthum, A rubrum,
 and A. saccharinum. Primarily showing leaf cuticle micromorphology on the
 ab- and adaxial surfaces.Whole specimen images of
 Acer rubrumImages of herbarium
 specimens of Acer rubrum used for studying leaf micromorphology. Also,
 images of herbarium specimens representative of taxonomically important
 macromorphological traits in the species.Whole_Specimen_Images_Acer_Rubrum.zipWhole specimen images of Acer laurinumImages of herbarium specimens of Acer laurinum used for studying leaf micromorphology. Also, images of herbarium specimens representative of taxonomically important macromorphological traits in the species.Whole_Specimen_Images_Acer_Laurinum.zipWhole specimen images of Acer pycnanthumImages of herbarium specimens of Acer rubrum used for studying leaf micromorphology. Also, images of herbarium specimens representative of taxonomically important macromorphological traits in the species.Whole_Specimen_Images_Acer_Pycnanthum.zipWhole specimen images of Acer saccharinumImages of herbarium specimens of Acer saccharinum used for studying leaf micromorphology. Also, images of herbarium specimens representative of taxonomically important macromorphological traits in the species.Whole_Specimen_Images_Acer_Saccharinum.zip