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GENUS: Delphinium

Delphinium spp.—Larkspur; delphinium

FAMILY: Ranunculaceae—the Buttercup Family (see Actaea)

PHENOLOGY: Two species of Delphinium are encountered in Pennsylvania. Delphinium exaltatum Ait. flowers in July and August; D. tricorne Michx., in April and May.

DISTRIBUTION: Delphinium occasionally occurs in rich woods.

PLANT CHARACTERISTICS: The genus Delphinium has: irregular flowers; calyx: resembling a corolla; sepals: 5, unequal, blue, purple, or white, the upper one prolonged backward into a spur; petals: 4, the upper two inequilateral, each with a long spur extending into the spurred sepal, the lower two clawed, abruptly deflexed at the middle; stamens: numerous; pistils: 1-5; fruit: a follicle; leaves: palmately cleft.

POISONOUS PARTS: The seeds are highly toxic; the young foliage is less poisonous. Toxicity decreases with age of the plant. At flower-bud formation, Delphinium is half as toxic as in the juvenile stage, and at fruit maturation it is reduced to one-sixteenth. Poisoning in the post-flowering stage, prior to seed formation, is uncommon. Toxicity also varies from species to species.

SYMPTOMS: The alkaloids produce digestive disturbance, nervousness, weakness, uneasiness, depression, collapse, muscle spasms, and death by asphyxiation. In larkspur poisoning, nausea, bloating, and abdominal pain may be present. Postmortem: gross lesions: congestion of internal organs (especially kidneys and superficial vessels); histological lesions: acute catarrhal gastroenteritis with diffuse venous congestion.

POISONOUS PRINCIPLES: Numerous diterpenoid alkaloids are found in the genus, including delphinine, delphineidine, ajacine, and others. The dried ripe seeds of Delphinium contain calcatripine, as well as volatile oil, gum, resin, fixed oil, gallic, and aconitic acids Poisoning from percutaneous absorption may occur from excessive handling,

CONFUSED TAXA: Delphinium exaltatum has erect follicles, nontuberous roots, and bifid lower petals. Delphinium tricorne is a tuberous-rooted perennial with entire lower petals and divergent follicles.

Consolida ambigua (L.) Ball and Heywood (=Delphinium Ajacis L.) is an introduced annual larkspur flowering in the summer. It has one pistil and petals united into one, whereas Delphinium has 4 petals. Toxicity and symptoms are identical to Delphinium.

Aconitum spp. may be confused with Delphinium but lack the spurs. Aconitum has a solid, pithy stem and short-petioled leaves, whereas larkspurs have hollow stems and long-petioled leaves. Aconitum contains the toxin aconitine, which is highly poisonous. Symptoms include violent diarrhea and vomiting, muscular spasms and weakness, respiratory failure, convulsions, and death. Symptoms appear within a few hours after consumption of flowers, leaves, roots, or seeds.

SPECIES OF ANIMALS AFFECTED: Humans and most classes of livestock are affected by delphinium alkaloids. Sheep appear much less susceptible than cattle.

TREATMENT: (lla)(b); (5-2mg subcutaneously); (27); (6); for poisoned animals subcutaneous injections of physostigmine salicylate, pilocarpine hydrochloride. and strychnine sulfate in the rates 1 grain, 2 grains, and 1/2 grain respectively per 500-600 lb animal.

OF INTEREST: Seed extracts are used as a pediculicide in the treatment of head lice.

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