Common Name: EVENING-PRIMROSE FAMILY
Habit: Annual to perennial herb (to tree). Leaf: cauline or basal, alternate, opposite, or whorled, generally simple and toothed (to pinnately compound); stipules 0 or generally deciduous. Inflorescence: spike, raceme, panicle, or flowers 1 in axils; bracted. Flower: generally bisexual, generally radial, often opening at either dawn or dusk; hypanthium generally prolonged beyond ovary (measured from ovary tip to sepal base); sepals 4(2--7); petals 4(2--7, rarely 0), often fading darker; stamens 2 × or = sepals in number, anthers 2-chambered, opening lengthwise, pollen interconnected by threads; ovary inferior, chambers generally as many as sepals (sometimes becoming 1), placentas axile or parietal, ovules 1--many per chamber, style 1, stigma 4-lobed (or lobes as many as sepals), club-shaped, spheric, or hemispheric. Fruit: capsule, loculicidal (sometimes berry or indehiscent and nut-like). Seed: sometimes winged or hair-tufted.
Genera In Family: 22 genera, +- 657 species: worldwide, especially western North America; many cultivated (Clarkia, Epilobium, Fuchsia, Oenothera). Note: Gaura moved to Oenothera. Fuchsia magellanica Lam. naturalized in northern California.
eFlora Treatment Author: Warren L. Wagner & Peter C. Hoch, family description, key to genera, treatment of genera by Warren L. Wagner, except as noted
Scientific Editor: Robert W. Patterson, Bruce G. Baldwin.

Habit: Annual, from taproot, stems rarely present, to 25 mm. Leaf: mostly basal, or cauline on short stems, alternate, broadly sessile or clasping. Inflorescence: flowers 1 in axils of rosette, nodding in bud. Flower: opening at dawn; sepals 4, reflexed in pairs; petals 4, yellow, unspotted, strongly ultraviolet-reflective, fading red-orange; longer stamens opposite sepals, anthers attached near base, pollen grains 3-angled; ovary tip with sterile 0.4--18 cm projection that often breaks off in fruit, with clear abscission line at juncture between short hypanthium and fertile part of ovary, stigma hemispheric, +- = anthers and generally self-pollinated (or > anthers and cross-pollinating). Fruit: irregularly obovoid, sharply 4-angled with pointed wing near center top of each valve, +- sessile, very tardily dehiscent in distal 1/2 only, thick-walled (not distended by seeds), persistent for > 1 year, sessile. Seed: in 2 crowded rows per chamber, obovoid to narrowly obovoid, finely papillate or deeply pitted, tan or brown with dark patches.
Etymology: (Greek: four winged) Note: Incl in Camissonia in TJM (1993).
Reference: Wagner et al. 2007 Syst Bot Monogr 83:1--240
Unabridged Reference: Raven 1969 Contr US Natl Herb 37:161--396