ABSTRACT
Larkspur, stagger weed, poison weed, and cow poison are a few of the names that have been applied to the members of the holarctic genus Delphinium in North America. The poisonous properties of the larkspurs have been recognized almost since the beginning of agriculture. Early colonists in North America must have been aware of the toxic properties of the native larkspurs because of the similarities in their appearance to European species. A surprisingly meager amount of information exists in the literature on the life histories of larkspur taxa. Clinical signs of larkspur poisoning apparently result from general weakness thought to be brought about primarily by action of the alkaloids on neuromuscular function. The toxicity of larkspurs varies with the amount ingested, seasonal changes in the alkaloid content, the duration of the ingestion period, the species ingested, the part of the plant ingested, and the animal species ingesting the larkspur.
