Tall Larkspur (Common name)

General poisoning notes:

Tall larkspur (Delphinium glaucum) is a native herb found in central and western Canada. The plant is poisonous to cattle and can be poisonous to horses and sheep when ingested in higher amounts. In an experiment with Delphinium barbei (not found in Canada), six times as much plant material (per kilogram of body weight) was needed to poison sheep than to poison cattle. Why cattle are sensitive to larkspur poisoning is not understood. The alkaloid methyllycaconitine causes curare-like effects on the skeletal muscles and can cause motor paralysis, followed by death from asphyxiation (Nation et al. 1982, Cheeke and Schull 1985, Olsen and Manners 1989).

References:

  • Cheeke, P. R., Shull, L. R. 1985. Natural toxicants in feeds and poisonous plants. AVI Publishing Company, Inc., Westport, Conn., USA. 492 pp.
  • Olsen, J. D., Manners, G. D. 1989. Toxicology of diterpenoid alkaloids in rangeland larkspur (Delphinium spp.). Pages 291-326 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. I. Alkaloids. CRC Press, Inc., Boca Raton, Fla., USA. 335 pp.

Nomenclature:

Scientific Name:
Delphinium glaucum S. Wats.
Vernacular name(s):
tall larkspur
Scientific family name:
Ranunculaceae
Vernacular family name:
crowfoot

Go to ITIS*ca for more taxonomic information on: Delphinium glaucum

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

  • Alberta
  • British Columbia
  • Manitoba
  • Northwest Territories
  • Ontario
  • Quebec
  • Saskatchewan
  • Yukon Territory

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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Notes on Poisonous plant parts:

All parts of larkspur plants contain alkaloids. Cattle have been poisoned after browsing on the aboveground plant material. Sheep and horses have been experimentally poisoned by various larkspur species, but they are much more tolerant of the toxic alkaloids (Olsen and Manners 1989).

Toxic parts:

  • all parts
  • leaves
  • seeds

References:

  • Looman, J. 1984. The biological flora of Canada. 5. Delphinium glaucum Watson, tall larkspur. Can. Field-Nat., 98: 345-361.
  • Olsen, J. D., Manners, G. D. 1989. Toxicology of diterpenoid alkaloids in rangeland larkspur (Delphinium spp.). Pages 291-326 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. I. Alkaloids. CRC Press, Inc., Boca Raton, Fla., USA. 335 pp.

Notes on Toxic plant chemicals:

Methyllycaconitine, a diterpene alkaloid, is considered to be the most toxic of the alkaloids occurring in larkspurs that are likely to be grazed by cattle on rangelands. Many other alkaloids occur in larkspurs, but they are much less toxic than methyllycaconitine. The LD-50 of this chemical on mice is 3.2 mg/kg administered intravenously. It has a pronounced curare-like effect on skeletal muscle (Olsen and Manners 1989).

Toxic plant chemicals:

  • methyllycaconitine

References:

  • Looman, J. 1984. The biological flora of Canada. 5. Delphinium glaucum Watson, tall larkspur. Can. Field-Nat., 98: 345-361.
  • Olsen, J. D., Manners, G. D. 1989. Toxicology of diterpenoid alkaloids in rangeland larkspur (Delphinium spp.). Pages 291-326 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. I. Alkaloids. CRC Press, Inc., Boca Raton, Fla., USA. 335 pp.

Animals/Human Poisoning:

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

Cattle

No details about poisoning symptoms available.

Horses

No details about poisoning symptoms available.

Sheep

No details about poisoning symptoms available.

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