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. brachycarpum C. Presl

Annual 2–20 dm, glabrous and peeling below, strigose and generally glandular-hairy above
Leaves generally early deciduous, 10–50 mm, linear to narrowly elliptic, acuminate, generally folded along midrib, ± glabrous; petiole 0–4 mm
Flower: hypanthium 1.5–8(16) mm; sepals 2–8 mm; petals 2–15 mm, white to rose-purple; stamens < or = pistil; stigma sometimes 4-lobed
Fruit 15–35 mm, glabrous or glandular; pedicel 3–20 mm
Seed 1.4–2.7 mm, papillate
Chromosomes: 2n=24
Ecology: Common. Dry open woodland, grassland, roadsides
Elevation: < 3300 m.
Bioregional distribution: California Floristic Province (except Channel Islands), Modoc Plateau, White and Inyo Mountains
Distribution outside California: to British Columbia, South Dakota, New Mexico, also e Canada; introduced in s S.America
Flowering time: Jun–Sep
Synonyms: E. paniculatum Torr. & A. Gray including vars. laevicaule (Rydb.) Munz and tracyi (Rydb.) Munz
Highly variable, especially flower size. KR plants with large flowers, pollen shed singly, have been called E. p. var. jucundum (Rydb.) Trel
Horticultural information: SUN, DRN: 4, 5, 6 &IRR: 1, 2, 3, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.