J Syst Evol ›› 2018, Vol. 56 ›› Issue (3): 218-230.

• Research Articles •

Try Tri again? Resolving species boundaries in the Lomatium triternatum (Apiaceae) complex

James F. Smith1*, Donald H. Mansfield2, McKayla Stevens2, Edgar Sosa1, Mary Ann E. Feist3, Stephen R. Downie4, Gregory M. Plunkett5, and Mark Darrach6

1. 1Department of Biological Sciences, Boise State University, 1910 University Drive, Boise, ID 83725, USA
2Department of Biology, The College of Idaho, 2112 Cleveland Boulevard, Caldwell, ID 83605, USA
3Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA
4Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
5Cullman Program for Molecular Systematics, New York Botanical Garden, Bronx, NY 10458, USA
6Corydalis Consulting, Burke Museum Herbarium, P.O. Box 355325, Seattle, WA 98195, USA
• Received:2018-02-07 Accepted:2018-04-03 Published:2018-05-10

Abstract:

Species boundaries have traditionally been delimited by applying phenotypic characters to a morphological species concept. With an increased understanding of the complexities of speciation as a process, species concepts have proliferated while at the same time, the ability to gather greater numbers and types of molecular characters has expanded the means by which species can be delimited. Phylogenetic studies of molecular data provide an opportunity to identify reciprocally monophyletic groupsand have led to the identification of cryptic or nearly cryptic species in which subtle differences in phenotypes or ecological niches can be uncovered only after monophyletic groups have been identified. Here, we investigate evolutionary relationships among a group of species in the Lomatium triternatum complex using molecular phylogenetic analyses for all samples, and ecological parameters for two of the 38 species included in this study. The results indicate that there are more reciprocally monophyletic groups in this complex than had been estimated using phenotypic data alone. The ecological data show a clear differentiation for the one pair of sister species where ecological sampling was available, implying that divergence within this group may have resulted from environmental selection for soil preferences that have been strong enough to result in speciation.