The genus Cicuta in North America

Abstract

Four species of Cicuta (family Umbelliferae) are recognized for North America: C. maculata L. (2n = 22), C. douglasii (DC.) Coult. & Rose (2n = 44), C. virosa L. (2n = 22), and C. bulbifera L. (2n = 22). Cicuta maculata has 22 large somatic chromosomes, C. virosa has 22 small somatic chromosomes, C. bulbifera has 22 medium sized chromosomes, and C. douglasii has 22 large chromosomes and 22 small chromosomes. Four varieties of C. maculata are recognized: var. maculata, var. angustifolia Hook., var. victorinii (Fernald) Boivin, and var. bolanderi (S. Wats.) G. A. Mulligan, stat. nov. Cicuta mackenzieana Raup is considered conspecific with C. virosu. The nomenclature, distribution, and relationships of the North American species are given together with an identification key to species and varieties.