Related entry: Staphisagria
Larkspur Seed. N. F. IV. Delphinium. Lark's claw. Knight's spur.—It is described by the N. F. as "the dried seeds of Delphinium Consolida Linné or of Delphinium Ajacis Linné (Fam. Ranunculaceae), without the presence of more than 5 per cent. of foreign matter. Irregularly tetrahedral, or by pressure somewhat triangulate, acute at one end, obtuse or rounded at the other, about 2 mm. in length and equally broad or slightly narrower, surface black or blackish-brown, deeply and narrowly furrowed, the furrows intersecting so as to give a sharply tuberculate appearance to the surface, with serrate edges; testa crustaceous; kernel whitish, fleshy; embryo small, in fleshy endosperm. Odor very faint; taste bitter, afterward biting and acrid. Larkspur Seed yields not more than 7 per cent. of ash." N. F. Thomas C. Hopkins, of Baltimore, found in the seeds of Larkspur, delphinine, C22H35O6N, volatile oil, fixed oil, gum, resin, chlorophyll, gallic acid, and salts of potassium, calcium, and iron. (A. J. P., xi.) Rochebrune (Toxicol. Africaine, i) has separated alkaloids believed by him to be identical with delphinine from D. peregrinum L. and D. mauritanicum Coss. From the expressed juice of the larkspur aconitic acid was obtained by W. Wicke. (J. P. C., 1854.) Moreover, the seeds of the indigenous D. exaltatum Ait. are stated to have a physiological action similar to that of the larkspur. Larkspur is a common weed in the Western States, where it occasions death among grazing cattle. It is said to lose its toxicity during the flowering period. It is a showy annual, which has been introduced from Europe into the United States, where it has become sparingly naturalized, growing in old grain fields and flowering in June and July. The flowers are bitter and acrid. The seeds are the only part of the plant which is official. In large doses the seeds produce violent vomiting and purging, and are said to be diuretic. A tincture is official in the N. F. and has been used in spasmodic asthma and dropsy, but is mainly employed as a parasiticide in a manner similar to the preparations of staphisagria. Dose, ten minims (0.6 mil), gradually increased. Brett has found that D. peregrinum L., when growing, is very effective in the destruction of grasshoppers. (P. J., vol. xxi, 1891. See Staphisagria in Part I.)
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.