The family includes a number of popular garden plants, including evening primroses (Oenothera) and fuchsias (Fuchsia). Some, particularly the willowherbs (Epilobium) are common weeds in gardens and in the wild. One such species is fireweed (Chamerion angustifolium).
The family is characterised by flowers with usually four sepals and petals; in some genera, such as Fuchsia, the sepals are as brightly coloured as the petals.
The seeds are generally very small. In some genera, such as Epilobium, they have tufts of hairs and are dispersed on the wind. In others, such as Fuchsia, the seeds develop in juicy berry and dispersed by animals. The leaves are commonly opposite or whorled, but are spirally arranged in some species; in most, they are simple and lanceolate in shape. The pollen grains in many genera are loosely held together by viscin threads. Most bees cannot collect it, and only bees with specialized morphologies can effectively pollinate the flowers; nearly all bee taxa that visit the flowers are oligoleges specialized on the family Onagraceae.
The family is named after the genus Onagra (now known as Oenothera) in 1836 by John Lindley in the second edition of A Natural System of Botany.
Herbs, sometimes ± woody at the base, or shrubs. Stipules minute or 0. Leaves alternate or opposite, rarely whorled, simple, entire, lobed or pinnatifid. Flowers bisexual or (rarely) unisexual, actinomorphic, 4- or 5-merous (rarely 2-, 3- or 6-merous). A long hypanthium usually present (not in Ludwigia). Petals free, sometimes 0. Stamens usually twice as many as the sepals in 2 whorls. Ovary inferior. Style single, stigma variously shaped. Fruit usually a loculicidally or irregularly dehiscent capsule, 1-many-seeded.
Barcode of Life Data Systems (BOLD) Stats Specimen Records:738 Specimens with Sequences:944 Specimens with Barcodes:690 Species:190 Species With Barcodes:161 Public Records:254 Public Species:79 Public BINs:0