TY - JOUR
T1 - Specimen-based analysis of morphology and the environment in ecologically dominant grasses
T2 - The power of the herbarium
AU - McAllister, Christine A.
AU - McKain, Michael R.
AU - Li, Mao
AU - Bookout, Bess
AU - Kellogg, Elizabeth A.
N1 - Publisher Copyright:
© 2018 The Author(s) Published by the Royal Society. All rights reserved.
PY - 2019/1/7
Y1 - 2019/1/7
N2 - Herbaria contain a cumulative sample of the world’s flora, assembled by thousands of people over centuries. To capitalize on this resource, we conducted a specimen-based analysis of a major clade in the grass tribe Andropogoneae, including the dominant species of the world’s grasslands in the genera Andropogon, Schizachyrium, Hyparrhenia and several others. We imaged 186 of the 250 named species of the clade, georeferenced the specimens and extracted climatic variables for each. Using semi- and fully automated image analysis techniques, we extracted spikelet morphological characters and correlated these with environmental variables. We generated chloroplast genome sequences to correct for phylogenetic covariance and here present a new phylogeny for 81 of the species. We confirm and extend earlier studies to show that Andropogon and Schizachyrium are not monophyletic. In addition, we find all morphological and ecological characters are homoplasious but variable among clades. For example, sessile spikelet length is positively correlated with awn length when all accessions are considered, but when separated by clade, the relationship is positive for three sub-clades and negative for three others. Climate variables showed no correlation with morphological variation in the spikelet pair; only very weak effects of temperature and precipitation were detected on macrohair density. This article is part of the theme issue ‘Biological collections for understanding biodiversity in the Anthropocene’.
AB - Herbaria contain a cumulative sample of the world’s flora, assembled by thousands of people over centuries. To capitalize on this resource, we conducted a specimen-based analysis of a major clade in the grass tribe Andropogoneae, including the dominant species of the world’s grasslands in the genera Andropogon, Schizachyrium, Hyparrhenia and several others. We imaged 186 of the 250 named species of the clade, georeferenced the specimens and extracted climatic variables for each. Using semi- and fully automated image analysis techniques, we extracted spikelet morphological characters and correlated these with environmental variables. We generated chloroplast genome sequences to correct for phylogenetic covariance and here present a new phylogeny for 81 of the species. We confirm and extend earlier studies to show that Andropogon and Schizachyrium are not monophyletic. In addition, we find all morphological and ecological characters are homoplasious but variable among clades. For example, sessile spikelet length is positively correlated with awn length when all accessions are considered, but when separated by clade, the relationship is positive for three sub-clades and negative for three others. Climate variables showed no correlation with morphological variation in the spikelet pair; only very weak effects of temperature and precipitation were detected on macrohair density. This article is part of the theme issue ‘Biological collections for understanding biodiversity in the Anthropocene’.
KW - Andropogoneae
KW - Grassland dominants
KW - Herbarium
KW - Image analysis
KW - Plastome phylogeny
UR - http://www.scopus.com/inward/record.url?scp=85056731609&partnerID=8YFLogxK
U2 - 10.1098/rstb.2017.0403
DO - 10.1098/rstb.2017.0403
M3 - Article
C2 - 30455217
AN - SCOPUS:85056731609
SN - 0962-8436
VL - 374
JO - Philosophical Transactions of the Royal Society B: Biological Sciences
JF - Philosophical Transactions of the Royal Society B: Biological Sciences
IS - 1763
M1 - 20170403
ER -