Oenothera (Gr., wine, and, a hunt, the roots of some species being supposed to provoke a relish for wine), a genus of plants known as evening primrose, and belonging to the family onagraceoe. The family is showy, and includes the well known Fuchsia, gaura, Olarlcia, and others cultivated for their flowers. The genus oeiothera, except one Tasmanian species, is purely extra-tropical American, and includes about 100 species, all herbs, or at most slightly woody at base; the flowers have afour-lobed calyx, four petals, eight stamens, and one style, with a knob-like or four-lobed stigma; the parts of the flower, being adherent to the o^a-ry, appear as if situated at the top of it; the fruit is sometimes woody, variously shaped, and usually four-celled, with numerous seeds. The common evening primrose (Oe. biennis) is found almost all over North America, and being so widely distributed presents a number of well marked varieties; it is a biennial with a strong fleshy root and stems 3 to 5 ft. high; leaves ovate-lanceolate, often obscurely toothed and hairy or nearly smooth; the flowers are in a terminal leafy spike, large, yellow, and fragrant. In this as in others of the genus, the flowers open only at twilight, and fade the next morning; the opening takes place suddenly.
Several varieties of this are in cultivation. The largest and finest, called Oe. Lamarckiana, branches abundantly at the base, and forms a fine pyramidal plant with very numerous flowers 3 or 4 in. in diameter; the sudden opening of these at nightfall is strikingly beautiful. The cornmon form is cultivated in Europe, especially in Germany, for its roots, and known as German rampion; the root is 10 to 12 in. long, sometimes with lateral fibres and very white within; its cultivation is like that of the parsnip and similar vegetables. The roots, which have a nutty flavor, are boiled and dressed as salad, or served with white sauce like salsify, and are regarded as more easily digestible by weak stomachs than most other Vegetables. In this country it is hardly known in cultivation. The Missouri evening primrose (Oe. Missouri-ensis) has a large fleshy perennial root, from which proceed numerous prostrate spreading stems, bearing ashy-green leaves and bright yellow flowers 4 to 6 in. across; this (sometimes called Oe. macrocarpa) is the largest-flowered of all the species.
There is a group of white-flowered Oenotheras which turn rose-colored in fading; some prostrate species of this group are very abundant on the western plains; during the day their dull leaves are not noticeable, but as night approaches the traveller is surprised to see the sterile soil suddenly bloom out with a profusion of these flowers. Another group consists of yellow-flowered species which open in bright sunshine, and are called sun-drops; Oe. fruticosaand Oe. linearis, both common wild species, and occasionally cultivated, are examples of these. There is a very distinct set of species on the Pacific coast, which from some differences in the structure have been placed in a different genus, Godetia, a name by which they are retained in floricul-tural works and seed catalogues, though botanists regard them as a section of Oenothera. These have white, rose-colored, or purple petals, which are often fringed on the margin. Not only are the original species cultivated, but several well marked varieties have been obtained by cultivation.
The Oe. grandiflora, which has recently been introduced into cultivation under the name of Godetia Wliitneyi, is a native species having bluish flowers with a dark crimson spot in the centre, and is quite as showy as any of the florists' varieties; the godetias are all annuals.
Lamarck's Evening Primrose (Oenothera biennis, var. Lamarckiana).
Missouri Evening Primrose (Oenothcra macrocarpa).