Lupins or lupines are the members of the genus Lupinus in the legume family.
The flowers are produced in dense or open whorls on an erect spike. Each flower is 1-2 cm long, with a typical peaflower shape with an upper 'standard' or 'banner', two lateral 'wings' and two lower petals fused as a 'keel'.
Like most members of their family, the roots of lupines can fix nitrogen from the atmosphere into ammonia, thereby fertilizing the soil for other plants. This adaption allows lupines to be tolerant of infertile soils and capable of pioneering change in barren and poor quality prairie and savanna soils.