peppergrass, any species of the genus Lepidium, widely distributed peppery-tasting herbs of the family Cruciferae (mustard family). They commonly have toothed leaves, clusters of small usually white flowers, and little flat, roundish pods (actually capsules) that are often fed to tame birds, whence the name canary grass. Most species are weedy, but one—the garden cress ( Lepidium sativum )—is sometimes cultivated as an annual salad plant. Shepherd's-purse (genus Capsella ), often confused with peppergrass, has triangular pods. Peppergrass is classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.