Dodder, or Strangleweed, a parasitic plant of the morning-glory family. About 30 of the 170 species grow in North America. It is a vinelike plant whose leaves lack chlorophyll and consist of brown scales along the stem. It bears clusters of white, greenish, or pink flowers. Seeds drop to the ground, take root, and then send up thin, threadlike shoots that twist about the stem of a host plant. The shoots produce rootlike suckers that penetrate the host and extract juice from it. Eventually the dodder vine forms a netlike covering that smothers the host plant.

Some species of dodder are particularly well adapted for one type of host plant, whereas others live on a wide range of hosts. Some dodders are agricultural pests; they grow on crops such as alfalfa, clover, and hops. Dodder can be exterminated by tearing out its roots, by burning, or by spraying with herbicides.

Dodder makes up the genus Cuscuta of the morning-glory family, Convolvulaceae.