Onagraceae includes annual, biennial, or perennial herbs. Leaves are usually alternate, sometimes opposite, and can be entire, toothed, or lobed. Plants may occasionally have very short or no visible stems. Flowers are bisexual, mostly actinomorphic, and typically appear alone in the leaf axils, though they may also form spike- or raceme-like clusters. The fruit is usually a capsule, though sometimes it can be nutlike.