Gentianaceae, or the Gentian family, is a family of flowering plants of 87 genera and over 1500 species.
Flowers are actinomorphic and bisexual with fused sepals and petals. The stamens are attached to the inside of the petals (epipetalous) and alternate with the corolla lobes. There is a glandular disk at the base of the gynoecium, and flowers have parietal placentation. The inflorescence is cymose, with simple or complex cymes. The fruits are dehiscent septicidal capsules splitting into two halves, rarely some species have a berry. Seeds are small with copiously oily endosperms and a straight embryo. The habit varies from small trees, pachycaul shrubs to (usually) herbs, with ascending, erect or twining stems. Plants are usually rhizomatous. Leaves opposite, less often alternate or in some species whorled, simple in shape, with entire edges and bases connately attached to the stem. Stipules are absent. Plants usually accumulate bitter iridoid substances; bicollateral bundles are present. Ecologically, partial myco-heterotrophy is common among species in this family.
Distribution is cosmopolitan. The family consists of trees, shrubs and herbs showing a wide range of colours and floral patterns.
Economically, some species are cultivated ornamental plants and many species yield bitter principles used medicinally and in flavorings.