Root plant to fuel the process. In return, the plant takes nitrogen compounds produced from ammonia by the bacteria. The term root crops refers to any edible underground plant structure, but many root crops are actually stems, such as potato tubers. Edible roots include cassava, sweet potato, beet, carrot, rutabaga, turnip, parsnip, radish, yam and horseradish. Spices obtained from roots include sassafras, angelica, sarsaparilla and licorice. Sugar beet is an important source of sugar. Yam roots are a source of estrogen compounds used in birth control pills. The fish poison and insecticide rotenone is obtained from roots of "Lonchocarpus" spp. Important
Pringlea cress, the boiled leaves as tasting like "stale" (i.e., dried-out) cabbage, and the root as tasting like horseradish. The micropezid fly species "Calycopteryx mosleyi" is associated with this plant. Both are endangered by invasive rabbits which feed on the cabbage. Pringlea Pringlea antiscorbutica, commonly known as Kerguelen cabbage, is a flowering plant and the sole member of the monotypic genus Pringlea in the cabbage family, Brassicaceae. Its common name comes from the archipelago of its discovery, the Kerguelen Islands, and its generic name derives from Sir John Pringle, President of the Royal Society at the time of its discovery by