Chapter 29. Thicket Plants.
Black Indian Hemp. Apocynum cannabinum L.
OTHER COMMON NAMES—Canadian hemp, American hemp, amy-root, bowman's-root, bitterroot, Indian-physic, rheumatism-weed, milkweed, wild cotton, Choctaw-root,
The name "Indian hemp" is often applied to this plant, but it should never be used without the adjective "black." "Indian hemp" is a name that properly belongs to Cannabis indica, a true hemp plant, from which the narcotic drug "hashish" is obtained.
HABITAT AND RANGE—Black Indian hemp is a native of this country and may be found in thickets and along the borders of old fields thruout the United States.
DESCRIPTION OF PLANT—This is a common herbaceous perennial about 2 to 4 feet high, with erect or ascending branches, and, like most of the plants belonging to the dogbane family (Apocynaceae), contains a milky juice. The shortstemmed opposite leaves are oblong, lance shaped oblong or ovate-oblong, about 2 to 6 inches long, usually sharp pointed, the upper surface smooth and the lower sometimes hairy. The plant is in flower from June to August and the small greenish white flowers are borne in dense heads, followed later by the slender pods, which are about 4 inches in length and pointed at the apex.
OTHER SPECIES—Considerable confusion seems to exist in regard to which species yields the root which has proved of greatest value medicinally. The Pharmacopoeia directs that "the dried rhizome and roots of Apocynum cannabinum or of closely allied species of Apocynum" be used.
In the older botanical works and medical herbals only two species of Apocynum were recognized, namely, A. cannabinum L. and A. androsaemifolium L., altho it was known that both of these were very variable. In the newer botanical manuals both of these species still hold good, but the different forms and variations are now recognized as distinct species, those formerly referred to cannabium being distinguished by the erect or nearly erect lobes of the corolla, and those of the androsaemifolium group being distinguished by the spreading or recurved lobes of the corolla.
Among the plants that were formerly collected as Apocynum or varietal forms of it, and which are now considered as distinct species, may be mentioned in the following:
Riverbank-dogbane (A. Album Greene), which frequents the banks of rivers and similar moist locations from Maine to Wisconsin, Virginia and Missouri. This plant is perfectly smooth and has white flowers and relatively smaller leaves than A. cannabinum.
Velvet dogbane (A. pubescens R. Br.), which is common from Virginia to Illinois, Iowa and Missouri. The entire plant has a soft, hairy or velvety appearance, which renders identification easy, According to the latest edition of the National Standard Dispensatory it is not unlikely that this is the plant that furnishes the drug that has been so favorably reported upon.
Apocynum androsaemifolium is also gathered by drug collectors for Apocynum cannabinum. Its root is likewise employed in medicine, but its action is not the same as that of cannabinum and it should therefore not be substituted for it. It closely resembles cannabinum.
DESCRIPTION OF ROOTSTOCK—The following description of the drug as found in commerce is taken from the United States Pharmacopoeia: "Of varying length, 3 to 8 mm. thick, cylindrical or with a few angles produced by drying, lightly wrinkled, longitudinally and usually more or less fissured transversely; orange-brown, becoming gray-brown on keeping; brittle; fracture sharply transverse, exhibiting a thin brown layer of cork, the remainder of the bark nearly as thick as the radius of the wood, white or sometimes pinkish, starchy, containing lactiferous ducts; the wood yellowish, having several rings, finely radiate and very coarsely porous; almost inodorous, the taste starchy, afterwards becoming bitter and somewhat acrid."
COLLECTION, PRICES AND USES—The root of black Indian hemp is collected in autumn and brings from 8 to 10 cents a pound.
It is official in the United States Pharmacopoeia and has emetic, cathartic, diaphoretic, expectorant and diuretic proper, ties, and on account of the last-named action it is used in dropsical affections.
The tough, fibrous bark of the stalks of Black Indian Hemp was employed by the Indians as a substitute for hemp in making twine, fishing nets, etc.