Aristolochiaceae
The Aristolochiaceae are a family of flowering plants. Wild ginger (Asarum) and pipevine (Aristolochia) are the two genera included in this family. A number of other tropical and subtropical monocots commonly referred to as gingers are members of family Zingiberales. The Aristolochiaceae are basal dicots (paleodicots), most closely related orders Magnoliales, Laurales, Canellales, and Piperales, which form a monophyletic clade called the Magnoliids. Some newer classification schemes place the Aristolochiales in order Piperales, but it is still quite common for the Aristolochiaceae to be assigned their own order (Aristolochiales).Many members of Aristolochia and some of Asarumcontain the toxin aristolochic acid, which discourages herbivores and is carcinogenic in rats. Aristolochia itself is carcinogenic to humans.
Pipevine swallowtail butterflies lay their eggs on pipevine (Aristolochia species), and the larvae dine on the plant but are not affected by the toxin, which then offers the adult butterfly protection against predators.