Members of the Hydrophyllaceae family are annual to perennial herbs, or rarely shrubs, with alternate, usually hairy and sometimes glandular-hairy leaves without stipules. The flower cluster is frequently composed of one to several curled smaller clusters, and the flowers are generally blue or purple. They are also bisexual, radially symmetric, and have 5 free sepals and a united corolla with 5 lobes. The five stamens are inserted at the base of the corolla, and usually extend beyond its mouth, the filaments are alternate with the corolla lobes. The pistil has a 1- or 2-celled superior ovary and, generally, a two-forked style. The fruit is a capsule with one to many seeds.
The waterleaf family is a small family, having only about 25 genera and 250 species of wide distribution worldwide, best developed in western U.S. It contains such ornamental genera as Phacelia, Nemophila, and Wiegandia, but is not otherwise particularly important, economically speaking.