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 Patterson, Bruce G. Baldwin.

Common Name: WILLOWHERB
Habit: Annual to subshrub. Leaf: generally opposite proximally (or clustered in axils), generally +- fine-toothed; veins generally obscure. Inflorescence: generally raceme, bracted. Flower: radial or rarely +- bilateral; sepals 4, erect; petals 4, notched; stamens 8, anthers attached at middle, pollen grains generally shed in 4s, cream-yellow; ovary chambers 4, stigma generally club-like, occasionally 4-lobed. Fruit: straight, cylindric to club-like. Seed: generally in 1 row per chamber, generally with white, deciduous hair-tuft.
Species In Genus: 165 species: worldwide except tropics. Etymology: (Greek: upon pod, from inferior ovary) Note: Incl Boisduvalia, Zauschneria. Most taxa polyploid; many with anthers +- = stigma self-pollinated; many hybrids. Taxa with alternate leaves moved to Chamerion.
eFlora Treatment Author: Peter C. Hoch
Reference: Raven 1976 Ann Missouri Bot Gard 63:326--340; Wagner et al. 2007 Syst Bot Monogr 83:81--95