Indian Hemp (Dogbane)

Apocynum cannabinum
Family: 
Apocynaceae (dogbanes)
Description: 

A shrubby, upright perennial with opposite branches and milky sap. Flowers are tiny, 5-pointed bells, massed in cymes, white or greenish white, attractive to bees. Leaves opposite, smooth-edged, variable, oblong or lance-shaped, hairy or not hairy, with conspicuous petioles (stalks). Stems are reddish and often grow higher than the flower cluster.

Similar species: Spreading dogbane  (A. androsaemifolium) has larger flowers in looser (less dense) clusters. Its flowers are pink or white with red inside and the petal lobes spread. The leaves tend to droop or spread. The two dogbanes live in the same habitats and can produce hybrids that can make identifications tricky.

Size: 
Height: to 3-4 feet.
Habitat and conservation: 
Occurs in prairies, glades, forest openings, bottomland forests, margins of swamps, ponds and lakes, banks of streams and rivers, pastures, ditches, levees, roadways, waste places, and other open, disturbed areas. Curiously, most dogbane plants produce few seeds, even though insects avidly visit the flowers. Apparently these plants must be cross-pollinated, but insects don't seem to accomplish this. Most populations consist of one or a few large clones (genetically identical individuals).
Distribution in Missouri: 
Statewide.
Human connections: 
Stems have a tough, fibrous bark that can be used like hemp for making rope or tying. Native Americans were using it for cordage thousands of years ago. When bruised, all parts of the plant exude a toxic white juice; the plant has long been used for many medicinal purposes.
Ecosystem connections: 
The toxic juices make this plant inedible to most mammals, but several types of moths eat this plant as caterpillars. They build up the toxin in their bodies and become unpalatable to predators. The delicate cycnia (Cycnia tenera), a tiger moth, is found wherever dogbane grows in Missouri.
Shortened URL
http://mdc.mo.gov/node/17533