DOI: 10.5061/dryad.n5tb2rbs4
title: Disentangling the taxonomic variations within the high-Andean complex Gomphrena meyeniana (Gomphrenoideae, Amaranthaceae)

description: Gomphrena meyeniana is an extremely variable species from the Andean
 highlands, which has attracted the attention of many botanists because it
 is the world’s highest-elevation C4 eudicot and because of its wide
 morphological variability. It has the typical high-Andean plant
 morphology, with small leaves tightly clustered on a thick rootstock. The
 large range of morphological variation within this species, coupled with
 the varying opinions on the existence of several species or infra-specific
 taxa, and the lack of molecular information has made the clarification of
 the G. meyeniana complex a challenge. Our approach was to perform a broad
 spectrum molecular sampling to identify its phylogenetic position within
 Gomphrena genus and to perform a multivariate analysis to objectively
 differentiate taxa based on morphological characters. The ITS and trnL-F
 regions were analyzed individually and combined using Bayesian inference
 and maximum parsimony methods. To analyze the morphological characters we
 performed a clustering method (partitioning around medoids with the
 Gower’s dissimilarity algorithm). The molecular analyses supported the
 monophyly of the G. meyeniana complex but did not support segregation into
 varieties. The morphological analyses gathered the infra-specific taxa
 into only three varieties that can be easily distinguished through three
 simple characters: the presence of leaves on the flowering shoot, the
 habit of the flowering shoot, and the pilosity of the tepals. The
 varieties of G. meyeniana accepted here are var. meyeniana, var.
 caulescens, and var. flaccida. A dichotomous key to identify the
 infra-specific taxa is here presented and illustrated. The varieties
 tucumanensis, and conwayi were synonymized with var. caulescens, and var.
 meyeniana respectively.
description: Molecular Data: Total
 genomic DNA was extracted from silica-dried leaves using a modified CTAB
 protocol (Doyle and Doyle 1987). For herbarium specimens, DNA was isolated
 using the DNeasy plant mini kit (Qiagen, Hilden, Germany) following the
 manufacturer’s recommendations. ITS1 and ITS2 were amplified in one
 segment using the primers ITS 28S Fwd and ITS 18S Rev of Kadereit et al.
 (2005). The chloroplast trnL-F region was amplified in one or two
 fragments using primers c, d, e, and f described by
 Taberlet et al. (1991). The PCR amplification for nuclear and cpDNA
 regions was performed as described by Kadereit et al. (2005) and Bena et
 al. (2017), respectively. The PCR products were purified with Gel Band
 Purification Kit (PB-L, Buenos Aires, Argentina), following the
 manufacturer’s recommendations. Sequencing reactions were performed by
 Macrogen, Inc. (Seoul, Korea). Low-quality regions were trimmed from the
 chromatogram files, and reverse and forward sequences for each specimen
 voucher were assembled and edited using the software MEGA v.6 (Tamura et
 al. 2013). Sequences for each marker were then aligned using ClustalX v2
 (Larkin et al. 2007) with the default options. The alignment was checked
 and improved manually when necessary using the program MEGA v.6 (Tamura et
 al. 2013). The aligned data matrix is available from the Dryad Digital
 Repository (Bena et al. 2019). Morphological Data: The association between morphological
 variables was studied by calculating the Pearson correlation coefficient
 between attributes in the Hmisc package of R (R Core Team 2014). We
 discarded the highly correlated attributes (correlation value &gt;
 0.6) Fig.
 S3.