moonseed

Moonseed is the common name for plants in the genus Menispermum, most often Menispermum canadense, the Canadian moonseed. It is a perennial, deciduous climbing vine in the Ranunculaceae family. Native to eastern North America, it grows in moist woods, along streams, and in forest edges, often climbing over shrubs or small trees.

Moonseed twines with other vegetation and bears small, inconspicuous flowers in spring. In late summer to fall it produces clusters of small drupes. The fruits are initially green and later ripen to a dark purple to black color. The seeds inside are crescent-shaped, giving the plant its common name.

All parts of the plant contain alkaloids and are considered toxic if ingested. The seeds are especially poisonous and have been reported to cause gastrointestinal distress, dizziness, and more severe neurological symptoms in humans. Because of the toxicity, moonseed is not used as food. Handling is generally safe, but seeds should not be eaten, and children should be kept away from the fruit. Birds and some mammals may eat the fruit and disperse the seeds.

Moonseed is sometimes found in naturalized stands in native forests and can be encountered in woodland gardens or along shaded streams. It is not widely cultivated for ornamental use due to its toxicity.