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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]

EPILOBIUM

FIREWEED, WILLOW HERB

Peter C. Hoch

Annual to subshrub
Leaves generally opposite below (or clustered in axils), generally ± fine-toothed; veins generally obscure
Inflorescence: generally raceme, bracted
Flower radial or ± bilateral; sepals 4, erect; petals 4, generally notched; stamens 8, anthers attached at middle, pollen grains generally shed in 4's, generally cream-yellow; ovary chambers 4, stigma generally club-like
Fruit straight, cylindric to club-like
Seeds generally in 1 row per chamber, generally with white, deciduous hair-tuft
Species in genus: 171 species: worldwide except tropical
Recent taxonomic note: Epilobium angustifolium, Epilobium latifolium now treated in Chamerion. See Hoch 1999 Flora of Japan IIc: 241; Baum et al. 1994 Syst Bot 19:363–388.
Etymology: (Greek: upon pod, from inferior ovary)
Reference: [Raven 1976 Ann Missouri Bot Gard 63:326–340]
Incl Boisduvalia , Zauschneria. Most taxa polyploid; many with anthers ± = stigma self-pollinated; many hybrids.

Native

E. oreganum Greene

OREGON FIREWEED

Perennial 4–10 dm from leafy, basal shoots, ± glabrous, ± glaucous
Leaf 30–90 mm, narrowly lanceolate to narrowly ovate; veins reddish, conspicuous; petiole 1–3 mm
Inflorescence sparsely strigose
Flower: hypanthium 2.4–3 mm; sepals 6–10 mm; petals 10–15 mm, pink to rose-purple; stamens < pistil; stigma 4-lobed
Fruit 25–45 mm, hairy and glandular; pedicel 3–6 mm
Seed 0.9–1.3 mm, papillate-ridged
Chromosomes: 2n=36
Ecology: Bogs, small streams, ditches
Elevation: 500–1600 m.
Bioregional distribution: Klamath Ranges, Outer North Coast Ranges
Distribution outside California: sw Oregon
Synonyms: E. exaltatum Drew
Often confused with E. ciliatum , especially subsp. glandulosum.

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