Lupinus perennis (Indian beet, Old maid's bonnets, and Sundial lupine) is a medicinal plant in the Fabaceae family. It is widespread in the eastern part of the USA (from Florida to Canada), Canada (south of Ontario), and on the coasts of the Arctic Ocean, where it grows on sand hills.
It derives only rosette-like radical leaves in the first year of vegetation. Stalks are numerous, erect, striated, slightly pubescent. Leaflets are obovate, with a blunted apex or pointed spear, naked from above, sparsely pubescent from below; their number is 7-11. Petioles are longer than leaflets; stipules are very small, almost missing.
The inflorescence is long, sparsely flowered, sometimes almost verticilate. The calyx is silky, without bractlets; its upper labium with a protuberant basis, is integral or weakly emarginate, the lower one is integral, almost twice longer than upper. Floral bracts are styliform, shorter than the calyx, early falling. The corolla is purple or white, three times longer than the calyx. The vexillum is shorter than the wings. The carina is weakly ciliate. Pods are yellow-grayish-brown, with straight lines, necklace-shaped, short and closely hirsute, easy shattered, with 5-6 seeds. Seed is oval with a light hilum.
The Sundial Lupin is used as foodplants by the caterpillars of several lepidoptera. Among these are the Frosted Elfin (Callophrys irus) and the rare and endangered Karner Blue (Lycaeides melissa samuelis), whose caterpillars are not known to eat anything else but Sundial Lupin leaves.