ONAGRACEAE

EVENING PRIMROSE FAMILY

Warren L. Wagner, except as specified Peter H. Raven, Family Coordinator

Annual to tree
Leaves basal or cauline, alternate, opposite, or whorled, generally simple and toothed (to pinnately compound); stipules 0 or generally deciduous
Inflorescence: spike, raceme, panicle, or flowers solitary in axils; bracted
Flower generally bisexual, generally radial, opening at dawn or dusk; hypanthium sometimes prolonged beyond ovary (measured from ovary tip to sepal base); sepals generally 4(2–7); petals generally 4 (or as many as sepals, rarely 0), often "fading" darker; stamens generally 4 or 8(2), anthers 2-chambered, opening lengthwise, pollen generally interconnected by threads; ovary inferior, chambers generally 4 (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, or hemispheric
Fruit: capsule, loculicidal (sometimes berry or indehiscent and nut-like)
Seeds sometimes winged or hair-tufted
Genera in family: 15 genera, ± 650 species: worldwide, especially w North America; many cultivated (Clarkia, Epilobium, Fuchsia, Gaura, Oenothera )
Reference: [Munz 1965 North America Fl II 5:1–278]

OENOTHERA

EVENING PRIMROSE

Annual, biennial, perennial herb, generally from taproot
Leaves basal or cauline, alternate, generally pinnately toothed to lobed
Inflorescence: spike, raceme-like, or flowers in axils of upper, reduced leaves
Flower radial, generally opening at dusk; sepals 4, reflexed in flower (sometimes 2–3 remaining adherent); petals 4, yellow, white, rose, or ± purple, generally fading orangish to purplish, tip notched or toothed; stamens 8, anthers attached at middle; ovary chambers 4, stigma deeply lobed, generally > anthers and cross-pollinated (or ± = anthers and self-pollinated)
Fruit cylindric to 4-winged, straight to curved, generally sessile (base sometimes seedless, stalk-like)
Seeds in generally 2(1–3) rows per chamber, or clustered
Species in genus: 119 species: Am, some widely naturalized
Etymology: (Greek: wine-scented)
Reference: [Dietrich & Wagner 1988 Syst Bot Monogr 24:1–91]
Many species self-pollinated; some of these have chromosome peculiarities (ring of 14 in meiosis) and ± 50% pollen fertility; they yield genetically ± identical offspring; they are identified as Permanent Translocation Heterozygote.

Native

O. flava (A. Nelson) A.O. Garrett subsp. flava

Perennial, ± rosetted, green; hairs glandular, also generally minutely strigose; taproot fleshy
Stem ± 0
Leaf 3–36 cm, oblanceolate to oblong, irregularly pinnately lobed, ± fleshy
Inflorescence: flowers in axils
Flower: hypanthium 24–80 (150) mm; sepals 10–34 mm, free tips in bud 1–2(5) mm; petals 10–30(38) mm, yellow fading pale orange
Fruit 10–40 mm, 4–7 mm wide, narrowly ovate to elliptic; wings 2–6 mm wide
Seed 1.8–2.6 mm, obliquely wedge-shaped, minutely beaded, narrow-winged distally and along 1 margin
Chromosomes: 2n=14
Ecology: Drying depressions, streambanks, generally clay soils, sagebrush scrub to pinyon/juniper woodland
Elevation: 900–1600 m.
Bioregional distribution: Cascade Range, n High Sierra Nevada, Modoc Plateau
Distribution outside California: to s Canada, Colorado, Mexico
Generally self-pollinated
Horticultural information: TRY.