The sword bean (Canavalia gladiata) — named for its long, flat, sabre-shaped pod — is a vigorous tropical legume whose enormous immature pods are eaten as a green vegetable across South and Southeast Asia and East Asia. Picked young and tender, the flat pod snaps like a broad green bean, with a mild, faintly grassy, bean-like taste; left to mature it fills with large hard seeds that must be well cooked to be safe.