Papilionaceae

Papilionaceae is a former botanical name for a subfamily within the pea family, Fabaceae. This group is now officially recognized as Faboideae. The name Papilionaceae itself is derived from the Latin word "papilio," meaning butterfly, referring to the distinctive butterfly-like shape of the flowers in many species within this group. These flowers typically consist of a large upper petal, known as the standard or banner, two side petals called wings, and two lower petals fused together to form a keel.

The plants formerly classified under Papilionaceae are widespread and found on every continent except Antarctica. They encompass a vast array of species, including many economically important crops such as peas, beans, lentils, soybeans, peanuts, clover, and alfalfa. These plants are also known for their ability to fix atmospheric nitrogen, a process facilitated by symbiotic bacteria in their root nodules. This nitrogen fixation enriches the soil, making these plants valuable in crop rotation and as cover crops. The subfamily is characterized by its diverse growth habits, ranging from herbs and shrubs to trees and vines, and its flowers are often brightly colored. Despite the change in taxonomic classification, the term Papilionaceae is sometimes still encountered in older literature or informal discussions.