Heracleum lanatum Michx.
Heracleum maximum, cow parsnip (also known as Indian celery, Indian rhubarb or pushki) is the only member of the genus Heracleum native to North America. Its classification has caused some difficulty, with recent authoritative sources referring to it variously as Heracleum maximum or Heracleum lanatum, or as either a subspecies, H. sphondylium subsp. montanum, or a variety, H. sphondylium var. lanatum, of the common hogweed (H. sphondylium). The classification given here follows ITIS.
Cow parsnip is distributed throughout most of the continental United States except the Gulf Coast and a few neighboring states. It occurs from sea level to elevations of about 2,700 metres (9,000 ft), and is especially prevalent in Alaska. It is listed as "Endangered" in Kentucky and "Special Concern" in Tennessee. In Canada, it is found in each province and territory, except Nunavut. It may be weedy or invasive in portions of its range.
Cow parsnip is a tall herb, reaching to heights of over 2 metres (7 ft). The genus name Heracleum (from "Hercules") refers to the very large size of all parts of these plants. Cow Parsnip has the characteristic flower umbels of the carrot family (Apiaceae), about 20 centimetres (8 in) across; these may be flat-topped or rounded, and are always white. Sometimes the outer flowers of the umbel are much larger than the inner ones. The leaves are very large, up to 40 cm (16 in) across, and divided into lobes. The stems are stout and succulent. The seeds are 8–12 mm (0.3–0.5 in) long and 5–8 mm (0.2–0.3 in) wide.
The stems and leaves contain furocoumarins, chemicals responsible for the characteristic rash of erythematous vesicles (burn-like blisters) and subsequent hyperpigmentation that occurs after getting the clear sap onto one's skin. The chemical is photosensitive, with the rash occurring only after exposure to ultraviolet light. Because of this, phytophotodermatitis may occur after using a weed-eater to remove the plants on a sunny day.
Indigenous North Americans have had a variety of uses for cow parsnip. It could be an ingredient in poultices applied to bruises or sores. The young stalks and leaf stems were used for food once the outer skin was peeled off. The dried stems were used as drinking straws for the old or infirm, or made into flutes for children.
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- Jepson Manual species treatment
- Heracleum maximum in the CalPhotos Photo Database, University of California, Berkeley
- Images from the Connecticut Botanical Society
- Plants for a Future report on the species
- Norman F. Weeden (1996), A Sierra Nevada Flora, Wilderness Press, ISBN 0-89997-204-7
- "Heracleum maximum Bartram". PLANTS Profile. United States Department of Agriculture; Natural Resources Conservation Service. Retrieved 2008-03-30.
- Elizabeth L. Horn (1998), Sierra Nevada Wildflowers, Mountain Press, ISBN 0-87842-388-5
- University of Michigan Ethnobotany
- "FirstVoices- Ktunaxa. Plants: food plants: words.". Retrieved 2012-07-07.
- Chesnut, Victor King (1902). Plants used by the Indians of Mendocino County, California. Government Printing Office. p. 404. Retrieved 24 August 2012.