The genus Cicuta is one of many genera in the family Apiaceae, which is in the order Apiales. Apiaceae is also known as Umbelliferae, and both of these family names are permitted to be used by the International Code of Nomenclature for algae, fungi, and plants. In Europe, Cicuta was not distinguished from the similar genus Conium before the year 1500. The first mention of the genus in the United States was in the eighteenth century. Carl Linnaeus formally described three species in 1753. The type species is Cicuta virosa. The genus is now recognized to comprise four species: Other species names such as Cicuta bolanderi, Cicuta californica, and Cicuta curtissii are older names now recognized to be varieties of the widespread, morphologically variable Cicuta maculata. Cicuta maculata is now recognized to have four varieties: var. maculata, var. angustifolia, var. victorinii, and var. bolanderi. Phylogenetic analysis using the sequences of nuclear ribosomal DNA internal transcribed spacer (ITS) loci was not conclusive but seems to show that C. bulbifera and C. virosa are monophyletic, while C. douglasii may not be. It was also suggested a specimen from California may warrant recognition as a distinct species. Other common names for the genus in general include poison parsnip, beaver poison, wild carrot, wild parsnip, and false parsley. Similar species Members of the family Apiaceae bear close resemblance to each other, and have many characteristics in common. Cicuta spp. are often mistaken for edible plants such as kvanne (Angelica archangelica), wild celery (Apium graveolens), pignut (Conopodium majus), wild carrot (Daucus carota), wild parsnip (Pastinaca sativa), and water parsnip (Berula spp.). One of the more common misidentifications is between water hemlock and water parsnip; both have clusters of small white flowers shaped like umbrellas, and both have the same habitat near the shoreline of lakes and rivers. Differences between water parsnip and water hemlock include the water parsnip having leaves only once compound while the water hemlock has leaves which are two or three times compound. Water hemlock also has a large swelling at the stem base which water parsnip lacks. Additionally, water hemlock has bracts at the base of each small flower cluster, not at the base of the main flower head, while water parsnip has both bracts at the base of flowers and also at the main flower head. Additionally, there can be confusion between the various water hemlock species and poison hemlock