Asclepias verticillata (Scientific name)

General poisoning notes:

Eastern whorled milkweed (Asclepias verticillata) is a native plant found in fields in parts of southern Canada. It has caused poisoning in experimental feeding tests in sheep. Large quantities of fresh plant were administered with a balling gun at about 2.2% of body weight, causing symptoms of poisoning (Marsh and Clawson 1921). The early literature is rife with contradictions in determining the scientific names of various milkweeds. Asclepias verticillata was termed Asclepias verticillata var. geyeri in Marsh and Clawson (1921). For more information on Asclepias taxonomy see Woodson (1954).

References:

  • Clark, J. G. 1979. Whorled milkweed poisoning. Vet. Hum. Toxicol., 21: 431.
  • Marsh, C. D., Clawson, A. B. 1921. Poisonous properties of the whorled milkweeds Asclepias pumila and A. verticillata var. geyeri. U. S. Dept. Agric. Bull., 942. 14 pp.
  • Woodson, R. E. 1954. The North American species of Asclepias L. Ann. Mo. Bot. Gard., 41: 1-211.

Nomenclature:

Scientific Name:
Asclepias verticillata L.
Vernacular name(s):
eastern whorled milkweed
Scientific family name:
Asclepiadaceae
Vernacular family name:
milkweed

Go to ITIS*ca for more taxonomic information on: Asclepias verticillata

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

  • Manitoba
  • Ontario
  • Saskatchewan

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

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Toxic parts:

  • flower buds
  • leaves

References:

  • Clark, J. G. 1979. Whorled milkweed poisoning. Vet. Hum. Toxicol., 21: 431.

Toxic plant chemicals:

  • galitoxin

References:

  • Clark, J. G. 1979. Whorled milkweed poisoning. Vet. Hum. Toxicol., 21: 431.

Animals/Human Poisoning:

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

Sheep

General symptoms of poisoning:

Notes on poisoning:

Experimental feeding of fresh eastern whorled milkweed caused poisoning in sheep. The animals fell down and went through characteristic running movements. The head and jaws occasionally moved compulsively. The pulse was often weak. Ingesting 2.2% of body weight was necessary to produce serious poisoning in sheep. Animals do not normally eat these distasteful plants or other milkweeds (Marsh and Clawson 1921).

References:

  • Clark, J. G. 1979. Whorled milkweed poisoning. Vet. Hum. Toxicol., 21: 431.
  • Marsh, C. D., Clawson, A. B. 1921. Poisonous properties of the whorled milkweeds Asclepias pumila and A. verticillata var. geyeri. U. S. Dept. Agric. Bull., 942. 14 pp.

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