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.