General poisoning notes:

Giant hogweed (Heracleum mantegazzianum) is naturalized in south central Ontario. It has caused photosensitization in children after exposure to the plant followed by sunlight (Morton 1975). This plant has also been introduced into New York State, where children have also contracted dermatitis from it (Gunby 1980).

References:

Anon. 1970. The giant hogweed. Lancet, 2: 32.

Drever, J. C., Hunter, J. A. 1970. Hazards of giant hogweed. Br. Med. J., 3: 109.

Gunby, P. 1980. Keep away from that 'tree', folks! J. Am. Med. Assoc., 244: 2596.

Morton, J. K. 1975. The giant cow parsnip, Heracleum mantegazzianum Umbelliferae, in Canada. Can. Field-Nat., 89: 183-184.

Nomenclature:

Scientific Name: Heracleum mantegazzianum Somm. & Levier
 

Vernacular name(s): giant hogweed

Scientific family name: Umbelliferae

Vernacular family name: parsley

Go to ITIS*^ca for more taxonomic information on: Heracleum mantegazzianum

References:

Agriculture Quebec. 1975. Noms des maladies des plantes du Canada/ Names of plant diseases in Canada. , Quebec City, Que., Canada. 288 pp.

Alex, J. F., Cayouette, R., Mulligan, G. A. 1980. Common and botanical names of weeds in Canada/Noms populaire et scientifiques des plantes nuisibles du Canada. Revised. Agric. Can. Publ., Ottawa, Ont., Canada. 132 pp.

Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.

Scoggan, H. J. 1978, 1979. The flora of Canada. Nat. Mus. Nat. Sci. (Ottawa) Publ. Bot. 7(1)-7(4). 1711 pp.

Van Wijk, H. L. 1911. A dictionary of plant names. Martinus Nijhoff, The Hague, The Netherlands. 1444 pp.

Victorin, M. 1964. Flore Laurentienne. 2nd ed. Univ. Montreal, Montreal, Que., Canada. 952 pp.

Geographic Information

Ontario
 

References:

Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.

Boivin, B. 1966, 1967. Énumération des plantes du Canada. Provencheria 6. Nat. Can. (Que.) 93: 253-274; 371-437; 583-646; 989-1063. 94: 131-157; 471-528; 625-655.

Image or illustration

giant hogweed:

Images: images.google.com

Toxic parts:

all parts
plant juices
stems
 

References:

Anon. 1970. The giant hogweed. Lancet, 2: 32.

Drever, J. C., Hunter, J. A. 1970. Hazards of giant hogweed. Br. Med. J., 3: 109.

Gunby, P. 1980. Keep away from that 'tree', folks! J. Am. Med. Assoc., 244: 2596.

Morton, J. K. 1975. The giant cow parsnip, Heracleum mantegazzianum Umbelliferae, in Canada. Can. Field-Nat., 89: 183-184.

Notes on Toxic plant chemicals:

Giant hogweed contains furocoumarins (psoralens), which make human skin hypersensitive to sunlight, causing cellular damage at the surface. They absorb long-wave ultraviolet light and become photodynamic (Cooper and Johnson 1984).

Toxic plant chemicals:

furocoumarin
 

References:

Cooper, M. R., Johnson, A. W. 1984. Poisonous plants in Britain and their effects on animals and man. Her Majesty's Stationery Office, London, England. 305 pp.

Drever, J. C., Hunter, J. A. 1970. Hazards of giant hogweed. Br. Med. J., 3: 109.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Humans

General symptoms of poisoning:

blistering
erythema
skin, brown pigment of
 

Notes on poisoning:

Symptoms of phytophotosensitization include serious and extensive weeping blisters. The lesions often occur in a line where the person has brushed aside the stems. The bullae can be massive and irritating, and brown pigmentation may remain for years after healing Morton 1975, Gunby 1980).

References:

Anon. 1970. The giant hogweed. Lancet, 2: 32.

Drever, J. C., Hunter, J. A. 1970. Hazards of giant hogweed. Br. Med. J., 3: 109.

Gunby, P. 1980. Keep away from that 'tree', folks! J. Am. Med. Assoc., 244: 2596.

Morton, J. K. 1975. The giant cow parsnip, Heracleum mantegazzianum Umbelliferae, in Canada. Can. Field-Nat., 89: 183-184.