The larkspur of the crude-drug trade is an annual plant (Delphinium consolida), native of southern Europe, which has long been cultivated in this country as an ornamental and is now occasionally found growing wild. Another species of larkspur (Delphinium urceolatum) is native to this country and is said to have properties very similar to those of the European species. Larkspur seed is now used chiefly in remedies for external parasites.

These larkspurs thrive best in a rich sandy or gravelly soil. In heavy soils they are likely to suffer from root-rot, which materially reduces the yield. A rather dry climate is suitable for plants of this character. They do not bear transplanting well and seeds should be sown in the fall or very early in the spring where the plants are to stand. The soil should be well fined and the seed thinly sown in drills spaced according to the method of cultivation to be used. When up, the plants should be thinned to stand 8 inches or more apart in the rows. The necessary cultivation consists in keeping the soil between the rows and about the plants mellow and free from weeds during the growing season.

When the seed capsules are fairly ripe, the seed is harvested by collecting the tops, which should be cut before the seed capsules have become so brittle as to risk the loss of seed by shattering and which can be handled best in the early morning while damp and pliable. They should be cured in a well-ventilated place, sheltered from rain, and when thoroughly dry may be thrashed out and cleaned.

The wholesale price now quoted for larkspur seed is between 32 and 35 cents a pound.

The seed of a European species of larkspur (Delphinium staphisagria), commonly-called stavesacre, possesses medicinal properties and is recognized as an official drug. The wholesale price for stavesacre seed in June, 1920, was about 30 cents a pound.