Data from: An integrative approach to delimiting species in a rare but widespread mycoheterotrophic orchid.
Cite this dataset
Barrett, Craig F; Freudenstein, John V (2011). Data from: An integrative approach to delimiting species in a rare but widespread mycoheterotrophic orchid. [Dataset]. Dryad. https://doi.org/10.5061/dryad.8582
In the spirit of recent calls for species delimitation studies to become more pluralistic, incorporating multiple sources of evidence, we adopted an integrative, phylogeographic approach to delimiting species and evolutionarily significant units (ESU) in the Corallorhiza striata species complex. This rare, North American, mycoheterotrophic orchid has been a taxonomic challenge with regard to species boundaries, displaying complex patterns of variation and reduced vegetative morphology. We employed plastid DNA, nuclear DNA, and morphometrics, treating the C. striata complex as a case study for integrative species delimitation. We found evidence for differentiation of the endangered C. bentleyi (eastern USA) + C. striata var. involuta (Mexico) from the remaining C. striata (= C. striata s.s.; USA, Canada, Mexico). Corallorhiza striata involuta and C. bentleyi, disjunct by thousands of kilometers (Mexico-Appalachia), were genetically identical but morphologically distinct. In light of these findings, the C. striata complex represents three species: C. bentleyi, C. involuta, and a widespread C. striata s.s under the phylogenetic species concept. Bayesian coalescent estimation delimited four species, but more informative loci and a definitive species tree will be needed to place higher confidence in future analyses. Three groupings were identified within C. striata s.s., corresponding to C. striata striata, C. striata vreelandii, and Californian accessions, but these were not delimited as phylogenetic species. Each, however, comprises an ESU, based on morphology and DNA sequences from two genomes, warranting conservation considerations.