Le statut des Euphrasia borealis , E . nemorosa et E . stricta dans l'est de l'Amérique du Nord : une analyse numérique

• Published in: Canadian Journal of Botany
• Main Authors: Downie, Stephen R., Quintin, Andrée, McNeill, John
• Format: Article in Journal/Newspaper
• Language: French
• Published: Canadian Science Publishing 1988
• Subjects: Plant Science; Newfoundland
• Online Access: http://dx.doi.org/10.1139/b88-303; http://www.nrcresearchpress.com/doi/pdf/10.1139/b88-303

The taxonomic status of Euphrasia borealis, E. nemorosa, and E. stricta in eastern North America has been the subject of considerable controversy. A sample of 184 operational taxonomic units were scored for 58 morphological characters, and the resulting data matrix was subjected to cluster and principal component analyses. Two groups were recognized on the basis of bract and upper cauline leaf characters and designated as E. nemorosa and E. stricta. These two groups were then subjected to several discriminant analyses (stepwise, linear, and canonical) using quantitative data. The results do not support the recognition of E. borealis and E. nemorosa as separate taxa. These plants should be treated as a single species, for which the correct name is E. nemorosa. Euphrasia stricta is, however, morphologically distinct from E. nemorosa. Some geographic differentiation was observed between plants of E. nemorosa from Newfoundland and those from Quebec, but not enough to warrant the recognition of infraspecific taxa. No evidence of hybridization between E. nemorosa and E. stricta was found. Key words: Euphrasia borealis, Euphrasia nemorosa, Euphrasia stricta, numerical analysis, North America, hybridization.