Varieties of Melampyrum lineare (Orobanchaceae) Revisited

Patterns of morphological variation within the North American annual hemiparasite, Melampyrum lineare, are reexamined in this study of its four varieties: M. lineare var. americanum, M. lineare var. latifolium, M. lineare var. lineare, and M. lineare var. pectinatum. Data were collected from 248 herbarium specimens drawn from the species' geographic range in Canada and the United States and included 45 vegetative, reproductive, and ecological characters. Each variety was found to have a broader distribution than previously reported, which expanded the area of known sympatry among the varieties to include most of the species' range. Multivariate analysis of variance revealed statistically significant differences in morphology among the four varieties (p