Bur buttercup-Ceratocephalus testiculatus (Crantz) Roth-Poisonous plant

Bur buttercup

General poisoning notes:

Bur buttercup (Ceratocephalus testiculatus) is an introduced herb that so far is known only from around Kamloops, British Columbia. This plant is found in several western states bordering Canada, where it is rapidly spreading. The plant has also been found on South Bass Island in Ohio on Lake Erie. This plant contains ranunculin, as do some species of the genus Ranunculus (buttercup). This chemical changes into a toxic chemical when the plant is crushed. Sheep have been poisoned and have died in the western United States after ingesting aboveground plant material; this plant is considered highly toxic. About 500 g of green plant can kill a 45-kg sheep. This plant grows in dry sandy areas, such as sage slopes and in livestock pens, and has recently been found as a weed in grain and alfalfa fields (Olsen et al. 1983, Cusick 1989).

Nomenclature:

Scientific Name: Ceratocephalus testiculatus (Crantz) Roth

Vernacular name(s): bur buttercup

Scientific family name: Ranunculaceae

Vernacular family name: crowfoot

Geographic Information

British Columbia

Toxic parts:

Plant juices

Notes on Toxic plant chemicals:

Crushing the plant releases an enzyme that changes ranunculin, a glycoside, to protoanemonin, a highly irritant, yellow, volatile oil. This chemical is unstable and changes to nontoxic anemonin or volatilizes upon drying, leaving nontoxic plant material. The median LD₅₀ was 10.9 g/kg for sheep fed aboveground plant parts in the flower to early-seed stage. A sheep fed 7 g/kg of body weight might develop transient anorectic effects. Intake of 13.9 g/kg or greater would usually be lethal (Olsen et al. 1983).

Toxic plant chemicals:

Ranunculin

Chemical diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia, Canada.

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:

Anorexia, breathing, labored, death, diarrhea, dyspnea, recumbency, weakness.

Notes on poisoning:

In Utah 150 of 800 sheep that ingested bur buttercup died. Symptoms took less than 24 h and included watery diarrhea, recumbency, weakness, and death. Experimental feeding showed more complete signs, such as tachycardia, dyspnea, anorexia, and occasional fever. Post- mortem findings revealed edema of the peritoneal surface to the ruminoreticulum, subendocardial hemorrhages in the left ventricle, and congestion of the heart, kidneys, liver and lungs. Severity was directly related to the dosage. Death results apparently as a failure of the cardiovascular system, with massive fluid shifts (Olsen et al. 1983).