The Evening Primrose or Willow herb family - Onagraceae - comprises about 20 genera and 700 species of annual or perennial plants that live throughout the world. They are mainly herbs, but we also find trees and shrubs. Some genera such as Fuchsia or Oenothera are very valuable in gardening. Most species are found in temperate regions of the New World. The flowers of this family are usually radially symmetrical, has 4 petals and 4 sepals, mostly separate, and growing in tall or branched clusters. The flower parts are attached at the top of the ovary. Number of stamens are 4 to 8, generally 8 and the pistil is single with a 4-lobed stigma in many cases. The plants have leaves that are simple, alternate or opposite, without stipules. The fruits are commonly contained in an long 4-chambered capsule and carry a white tuft of hair for wind dispersal.
Guide to Identify Presented Species of the Evening Primrose Family
FLOWERS PINK, PURPLE OR WHITE. SEEDS WITH HAIR TUFT
Epilobium Fireweed, Willowherb Annuals or perennials, 15-200 cm tall, branched or simple. Dry or moist sites.
Flowers white to pink or purple, 5-20 mm wide, the 4 petals often notched.
Leaves alternate or opposite, mostly lance-shaped, 2-10 cm long, often entire.
FLOWERS WHITE, PINK OR YELLOW, AT LEAST 3 CM BROAD
Oenothera Evening Primrose Low or tall annuals or perennials. Often in plains and hills, in sandy soils.
Flowers white, pink or yellow, with 4 broad petals, single or from leaf axils.
Leaves basal or alternate, with wavy margins, entire or toothed or lobed.
Alphabetical listing with links to presented species of the Evening Primrose family: