Peucedanum palustre

Peucedanum palustre (milk-parsley) is an almost glabrous biennial plant in the family Apiaceae. It is so called in English because of the thin, foetid, milky latex found in its young parts and is native to most of Europe, extending eastwards to Central Asia. Another English common name for the plant is marsh hog's fennel (hog's fennel (unqualified) and sea hog's fennel, by contrast, are common names of Peucedanum officinale, a perennial species in the same genus, found in drier habitats, but having similar medicinal properties). Peucedanum palustre grows (as its specific name implies) in wetlands, shallow water at the margins of rivers and estuaries and occasionally in ditches and other smaller water features. It is relatively shade-tolerant and requires seasonal submerging of the site to compete with other plants. It is well-known to lepidopterists as the main foodplant of the Old World swallowtail. Cambridge milk parsley is the common English name of a different plant: Selinum carvif......read more on Wikipedia.