A multivariate analysis of Pseudocymopterus (Apiaceae)

SUN, F.-J. (Department of Plant Biology, 505 South Goodwin Avenue, University of Illinois, Urbana, IL 61801), G. A. LEVIN (Center for Biodiversity, Illinois Natural History Survey, 1816 South Oak Street, Champaign, IL 61820), AND S. R. DOWNIE (Department of Plant Biology, 505 South Goodwin Avenue, University of Illinois, Urbana, IL 61801). A multivariate analysis of Pseudocymopterus (Apiaceae). J. Torrey Bot. Soc. 133: 499–512. 2006.–Currently, Pseudocymopterus comprises two species, P. montanus and P. longiradiatus. Pseudocymopterus montanus is highly variable morphologically and in the past was subdivided into several poorly defined taxa. Multivariate analyses of 235 specimens reflecting the morphological variability exhibited by these plants and representing populations from throughout the ranges of both species were conducted to examine morphological discontinuities in Pseudocymopterus. Multivariate analysis of variance and principal component analysis confirmed that most of the characters previously used to recognize taxa within the complex are highly variable and overlapping among putative taxa. While no clearly distinguished clusters were revealed on the plots of the first three principal components, groups corresponding to P. montanus and P. longiradiatus were weakly separated from each other. Discriminant analysis using the same set of specimens showed that P. montanus and P. longiradiatus can generally be distinguished using a set of characters. These results are consistent with recent molecular analyses that revealed DNA sequence differences between these taxa. We therefore propose that Pseudocymopterus continues to be treated as having two species, P. longiradiatus and P. montanus, with no infraspecific taxa.