A multivariate morphological analysis of the Cardamine concatenata alliance (Brassicaceae)

Principal coordinate analysis using Gower's similarity coefficient and cano nical discriminant analysis were performed using morphological data to asse ss species distinctness in the Caradamine concatenata alliance, comprising the eastern North American dentarias. The results of an overall principal c oordinate analysis of the alliance using quantitative and qualitative chara cters revealed distinct and separate clusters that correspond to Rye previo usly recognized species (C. angustata, C. concatenata, C. diphylla, C. diss ecta, C. maxima). One additional taxon, C. incisa, was found to group close ly with the C. diphylla cluster. In a second principal coordinate analysis including only individuals from C. diphylla and C. incisa, both are support ed as distinct morphological entities. Canonical discriminant analysis of o nly above-ground quantitative characters was less effective in distinguishi ng previously recognized taxa, in keeping with the emphasis on qualitative characters in previous taxonomic treatments of the group. Cardamine incisa (Eames) Schumann (pro hybr.) is raised to the rank of species. A key to the species of the Cardamine concatenata alliance is provided.