Synonyms: Other names: dogsbane, milkweed Nomenclature: androsaemifolium = leaves like Androsaemum Nativity / Invasiveness: Montana native plant
General: perennial herb with milky juice, freely branched, hairless to slightly woolly-hairy, 20-70 cm tall, from spreading rhizomes.
Leaves: opposite, short-stalked to almost stalkless, spreading to drooping, oblong-elliptic to ovate, oval, or cordate-ovate, 25-70 mm long, hairless above, lighter and somewhat hairy beneath, usually with an abrupt blunt tip.
Flowers: several in few-flowered clusters at stem tips and from leaf axils. Corolla pinkish to white with pink veins, mostly 5-10 mm long, from tubular and of nearly uniform diameter from the base to the limb, to distinctly bell-shaped and nearly twice as broad at the limb as at the base, the 5 lobes oblong-lanceolate, about 1/2 the length of the tube, erect to spreading or slightly bent back. Calyx 1/4-1/2 the length of the corolla tube, the lobes ovate and rounded to lanceolate and somewhat pointed.
Fruits: cylindrical follicles in pairs, 5-14 cm long, erect to hanging. Seeds many, 2.5-3 mm long, tipped with white to tawny hairs, 1-2 cm long.
Wooded or dry, open areas, plains to subalpine zones, in w., s.c. and s.e. parts of MT, in many places a serious orchard weed. Also throughout much of Canada and most of the U.S. except in the s.e. parts.
Spreading dogbane is an unpleasantly bitter stimulant irritant herb that acts on the heart, respiratory and urinary systems, and also on the uterus. It was widely employed by the native North American Indians who used it to treat a wide variety of complaints including headaches, convulsions, earache, heart palpitations, colds, insanity and dizziness. The root has properties that are tonic for the heart, strong laxative, induce perspiration, and that produce urine, induce vomiting and coughing. It has a powerful action in slowing the pulse and also has a very strong action on the vaso-motor system, it is rather an irritant to the mucous membranes though, so some people cannot tolerate it. The juice of the fresh root has been used in the treatment of syphilis. The sap of the plant has been applied externally to get rid of warts. The roots were boiled in water and the water drunk once a week in order to prevent conception. The green fruits were boiled and the decoction used in the treatment of heart and kidney problems and for the treatment of dropsy. However, this preparation can irritate the intestines and cause unpleasant side effects.
Toxic glycosides in the milky sap can raise blisters on sensitive skin. These toxins help protect the plant from browsing animals. Its medicinal use has resulted in sickness and death. It should be used with great caution, and only under the supervision of a qualified practitioner if taking this plant internally. The root contains cymarin, a cardioactive glycoside that is toxic to ruminants. Experimental evidence shows that spreading dogbane contains apocynamarin, a cardiac glycoside, as well as other glycosides and resins. These chemicals have caused sickness and death when administered cats and dogs. The potential for poisoning therefore exists.
The tough fibers from the bark of the stems of dogbanes were rolled against the leg to make thread, which was said to be stronger and finer than cotton thread. It was also used to make rabbit nets used in communal rabbit hunts. It can be harvested after the leaves fall in the autumn but is probably at its best as the seed pods are forming. The plant yields a latex, which is a possible source of rubber. It is obtained by making incisions on the stem and resembles indiarubber when dry.
ssp. androsaemifolium L: Corolla bell-shaped, 5-10 mm long. Follicles usually hanging. Flower cluster terminal, simple. With the range of the species.
ssp. pumilum Gray: Corolla more tubular, 4-7 mm long. Follicles usually erect. Flower cluster frequently larger and partially from leaf axils as well as terminal. In most of w. U.S. and Canada.
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