Pachyrhizus erosus, commonly known as jicama Mexican yam bean, or Mexican turnip, is the name of a native Mexican vine, although the name most commonly refers to the plant's edible tuberous root. Jícama is a species in the genus Pachyrhizus in the bean family (Fabaceae). Plants in this genus are commonly referred to as yam bean, although the term "yam bean" can be another name for jícama. In contrast to the root, the remainder of the jícama plant is very poisonous; the seeds contain the toxin rotenone, which is used to poison insects and fish. FAO: The yam bean is a legume but unlike its close relatives the soybean and other beans, the yam bean is cultivated for its large, tuberous roots.