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. caespitosa Nutt.

FRAGRANT EVENING PRIMROSE

Perennial, rosetted; caudex woody, new shoots generally from lateral roots; hairs glandular and sometimes also coarse and non-glandular
Stem sprawling, < 2 dm, or ± 0
Leaf 1.7–36 cm, oblanceolate to narrowly elliptic, generally irregularly dentate to lobed
Inflorescence: flowers in axils
Flower: hypanthium 30–165 mm; sepals 16–50 mm, tips in bud not free; petals 16–56 mm, white
Fruit 10–68 mm, 4–9 mm wide, cylindric to elliptic-ovate, tubercled
Seed obovate to ± triangular, papillate or netted, 1 side with a cavity sealed by a depressed, generally splitting membrane
Chromosomes: 2n=14,28
Ecology: Open desert scrub, pinyon/juniper woodland, coniferous and bristlecone-pine forests
Elevation: 1100–3400 m.
Bioregional distribution: Modoc Plateau (likely), East of Sierra Nevada, Desert
Distribution outside California: w US
Cross-pollinated. 5 intergrading subspp., 2 in CA.

Native

subsp. crinita (Rydb.) Munz

CAESPITOSE EVENING PRIMROSE

Plant loosely to densely cespitose
Flower: hypanthium 30–85 mm; petals fading rose to purple
Fruit 10–34 mm, lanceolate to elliptic-ovate, generally S-shaped; stalk-like base 0–1 mm
Seed 2.9–3.5 mm; cavity margin lobed
Ecology: UNCOMMON. Calcium soils in bristlecone-pine forest, pinyon/juniper woodland, desert scrub
Elevation: 1150–3370 m.
Bioregional distribution: Modoc Plateau (likely), East of Sierra Nevada, Desert
Distribution outside California: w US
Flowering time: Jun–Sep
Synonyms: var. c. (Rydb.) Munz
2 intergrading forms differ in elevation, habit, leaf size, petal color; more study needed
Horticultural information: TRY.