Jepson Flora Project: Jepson Interchange    

 
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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.

Introduced

O. speciosa Nutt.

Perennial, rosetted when young, forming large patches from woody caudices and rhizomes, minutely strigose (some hairs also longer)
Stem weakly ascending to erect, 1–5 dm
Leaves: cauline 2.5–8 cm, oblanceolate to ± elliptic, subentire to wavy-lobed
Inflorescence: flowers in upper axils; stem tip nodding
Flower: hypanthium 10–23 mm; sepals 15–30 mm, free tips in bud 1–4 mm; petals 25–40 mm, white fading pink or rose-purple
Fruit 10–25 mm, widening upward (to 3–5 mm), 8-ribbed; stalk-like base (4)8–15 mm, 1.5–2 mm wide, cylindric
Seeds clustered in each chamber, 1–1.5 mm, obliquely oblanceolate, finely granular-papillate
Chromosomes: 2n=14,28,42
Ecology: Disturbed places
Elevation: generally < 500 m.
Bioregional distribution: Western Transverse Ranges
Distribution outside California: native New Mexico to c US, c Mexico
Synonyms: var. childsii (L.H. Bailey) Munz
Commonly cultivated. Cross-pollinated.

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