The bottle gourd (Lagenaria siceraria) — also called calabash, lauki, opo or white-flowered gourd — is a fast-growing vine fruit eaten young as a mild, watery vegetable and dried when mature into a hard-shelled vessel. Picked green and immature it has pale, spongy white flesh and a clean, faintly cucumber-like taste that readily takes on the flavours it is cooked with.