This pretty, delicate native of Europe and Asia was introduced into the vicinity of Boston, and has become very common in fields and roadsides from New Brunswick and Ontario southward to New Jersey, Illinois, and Iowa, throughout the summer. The smooth, leafy perennial stalk branches at the base, and grows from six to eighteen inches high. The oblong or lance-shaped, dark green leaves occur in alternate pairs, and are variable in size. They are acutely pointed, and the lower ones are often paddle shaped. The white flowers are arranged in loose, often drooping clusters, and are fragrant only at night. The five clawed petals are deeply cleft and wheel shaped. Ten long stamens extend beyond the corolla. The strongly veined, five toothed, pale green calyx is greatly swollen and strongly hints its common name. It is also the most distinguishing feature of the flower. In some parts of England, country people cook and eat the young shoots of this plant as a substitute for asparagus. It is said to have a flavour much like green peas.