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
Capparis also used for cooking; "C. mitchellii" and the Wild passionfruit (the local subspecies of "C. spinosa") are well-known bush tucker in Australia. Mabinlang seeds ("C. masaikai") are eaten as sweets. Mabinlang is also used in Traditional Chinese Medicine. "Aspalathos", the root of a shrub contained for example in the sacred Ancient Egyptian incense "kp.t" (kyphi), is sometimes considered to be "C. spinosa". Other species have also recorded uses in herbalism and folk medicine; dedicated research is largely lacking however. Mabinlins are sweet-tasting proteins found in Mabinlang seed (and possibly in other "Capparis" species); at least one of them is highly