The Jepson Herbarium
		University of California, Berkeley

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Annual to subshrub.
Leaf: generally opposite proximally (or clustered in axils), generally ± fine-toothed; veins generally obscure.
Inflorescence: generally raceme, bracted.
Flower: radial or rarely ± bilateral; sepals 4, erect; petals 4, notched; stamens 8, anthers attached at middle, pollen grains generally shed in 4s, cream-yellow; ovary chambers 4, stigma generally club-like, occasionally 4-lobed.
Fruit: straight, cylindric to club-like.
Seed: generally in 1 row per chamber, generally with white, deciduous hair-tuft.
165 species: worldwide except tropics. (Greek: upon pod, from inferior ovary) [Raven 1976 Ann Missouri Bot Gard 63:326–340; Wagner et al. 2007 Syst Bot Monogr 83:81–95] Incl Boisduvalia, Zauschneria. Most taxa polyploid; many with anthers ± = stigma self-pollinated; many hybrids. Taxa with alternate leaves moved to Chamerion.

Key to Epilobium

1. Annual from taproot; leaves opposite only near base, alternate or clustered distally, ± narrowly lanceolate; proximal stem generally peeling

2. Seed hair-tuft 0

3. Fr wall tough, generally splitting only on distal 1/3; seeds in 2 rows per chamber; basal branches generally prostrate or decumbent (sect. Epilobiopsis)

4. Fr 8–12 mm, sharply 4-angled ..... E. cleistogamum

4' Fr 3.5–8 mm, cylindric ..... E. campestre

3' Fr wall flexible, splitting to base; seeds in 1 row per chamber or compressed to 1 row per capsule; basal branches ascending or 0 (sect. Boisduvalia)

5. Fr not beaked, central axis persistent ..... E. densiflorum

5' Fr beaked, central axis disintegrating

6. Hypanthium 1.5–3 mm, sepals 2–6 mm, petals 3–10 mm; fruit 10–21 mm; seeds in 1 staggered row, 1.8–2.3 mm ..... E. pallidum

6' Hypanthium 0.4–1 mm, sepals 0.7–2 mm, petals 1–3.2 mm; fruit 8–14 mm; seeds in 4 rows, 0.9–1.6 mm ..... E. torreyi

2' Seed hair-tuft present

7. Plant 2–20 dm, ± glandular; hypanthium 1.5–8(16) mm, sepals 1.2–8 mm, petals 2–15(20) mm; seed 1.5–2.7 mm ..... E. brachycarpum

7' Plant 0.5–4.5 dm, nonglandular; hypanthium 0.4–1.5 mm, sepals 1.3–2.5 mm, petals 1.8–5 mm; seed 0.6–1.2 mm

8. Lvs generally folded along midrib, distal clustered; inflorescence dense; petals 1.8–3 mm; seeds 0.6–0.9 mm, papillate ..... E. foliosum

8' Lvs flat, not clustered; inflorescence open; petals 2–5 mm; seeds 0.9–1.2 mm, netted ..... E. minutum

1' Perennial to subshrub from caudex, taproot 0; leaves generally opposite up to inflorescence, generally (narrowly) lanceolate to ovate; proximal stem not peeling (except Epilobium rigidum)

9. Hypanthium 17–34 mm; corolla red-orange, ± bilateral (sect. Zauschneria)

10. Matted per 1–2 dm; proximal leaves white-canescent, nonglandular, distal leaves glandular; NCo, NCoRO ..... E. septentrionale

10' Clumped perennial herbs to subshrub 1–12 dm; all leaves alike, generally not white-canescent, glandular or not; widespread CA-FP ..... E. canum

11. Lvs linear to lanceolate, generally < 6 mm wide, often clustered; perennial herb to subshrub 2–12 dm ..... subsp. canum

11' Lvs lanceolate to widely ovate, generally > 6 mm wide, not clustered; per 1–5 dm

12. Lvs widely ovate, prominently toothed, lateral veins conspicuous ..... subsp. garrettii

12' Lvs lanceolate to ovate, ± entire to generally toothed, lateral veins obscure ..... subsp. latifolium

9' Hypanthium generally 0.4–8(16) mm; corolla white or cream-yellow to purple (sect. Epilobium)

13. Stigma 4-lobed; sepals (3)6–15 mm; petals (6)10–24 mm, pink to rose-purple or cream

14. Petals cream-yellow; hair-tufts ± red, persistent; fruit 35–75 mm ..... E. luteum

14' Petals pink to rose-purple; hair-tufts white, deciduous; fruit 8–45 mm

15. St 4–10 dm; leaf 30–90 mm, veins ± red, conspicuous; seed 0.9–1.3 mm, ridged ..... E. oreganum

15' St < 4 dm; leaf 6–45 mm, veins obscure; seed 1.4–3.4 mm, papillate

16. Petals 6–10 mm; seeds 1–2 per chamber (8 per fruit); fruit 8–16 mm ..... E. nivium

16' Petals 11–24 mm; seeds > 8 per chamber; fruit 20–45 mm

17. Plant 1–4 dm, nonglandular; leaf 20–45 mm, petiole 2–6 mm; hypanthium 1–1.8 mm; seed 2.5–3.4 mm ..... E. rigidum

17' Plant < 2.5 dm, sometimes glandular (especially ovaries); leaf 6–26 mm, petiole 0–3 mm; hypanthium 2–6 mm; seed 1.4–2.1 mm

18. Pedicel in fruit 2–3 mm; leaf 6–20 mm, tip round to obtuse, petiole 0–3 mm; plant ± glaucous ..... E. obcordatum

18' Pedicel in fruit 6–25 mm; leaf 13–26 mm, tip ± acute; petiole 0; plant not glaucous ..... E. siskiyouense

13' Stigma entire, club-like (occasionally cylindric); sepals 1–7.5 mm; petals 1.6–14 mm, white to rose-purple

19. St ± erect, with offset rosettes or fleshy underground shoots

20. Lf veins ± obscure; stem with fleshy bulb-like shoot; seed papillate

21. Pedicel in fruit 10–40 mm; inflorescence ± nodding; leaf 5–45 mm ..... E. hallianum

21' Pedicel in fruit 0–5 mm; inflorescence erect; leaf 10–65 mm ..... E. saximontanum

20' Lf veins conspicuous; stem with rosette or fleshy shoot; seed ridged ..... E. ciliatum

22. Petals 2–6(9) mm, white to pink; leaf lanceolate, reduced in open inflorescence — basal rosette present ..... subsp. ciliatum

22' Petals 4–14 mm, pink to rose-purple; leaf lanceolate to ovate, little reduced on crowded inflorescence

23. St with fleshy shoot; inflorescence long ..... subsp. glandulosum

23' St with leafy rosette or shoot; inflorescence flat-topped ..... subsp. watsonii

19' St ± ascending, clumped or cespitose; leafy or thread-like stolons sometimes tipped by fleshy bulblets

24. Plant ± glabrous (except scattered inflorescence hairs)

25. Plant 0.8–3(4) dm, matted; stolons thread-like; pedicels 20–65 mm; inflorescence open (bracts << internodes); leaf tip obtuse ..... E. oregonense

25' Plant < 8.5 dm, clumped; stolons short, scaly; pedicels 5–25 mm; inflorescence crowded (bracts ± = internodes); leaf tip subacute ..... E. glaberrimum

26. St < 3.5 dm; leaf 10–35 mm, lanceolate to narrowly ovate; fruit 20–55 mm ..... subsp. fastigiatum

26' St 2–8.5 dm; leaf 20–70 mm, ± narrowly lanceolate; fruit 45–75 mm ..... subsp. glaberrimum

24' Plant variously hairy, often in decurrent lines on stem

27. St densely glandular-hairy; petals 2–3 mm, white ..... E. howellii

27' St hairy, nonglandular; petals 2–9 mm, white or pink to rose-purple

28. Stolons thread-like, tipped by fleshy bulblets; leaf ± narrowly lanceolate; seed 1.4–2.2 mm, hair-tuft persistent

29. Lf densely minutely strigose; inflorescence minutely strigose and glandular ..... E. leptophyllum

29' Lf minutely strigose only on margins and midrib; inflorescence minutely strigose, nonglandular ..... E. palustre

28' Stolons short, leafy; leaf generally lanceolate or wider; seeds 0.7–2.1 mm, hair-tuft generally deciduous

30. Plant cespitose, < 2.2 dm; leaf 8–28 mm; fruit 17–40 mm

31. Infl ± nodding; pedicel in fruit 10–55 mm; seed 0.7–1.4 mm, netted ..... E. anagallidifolium

31' Infl erect; pedicel in fruit 2–18 mm; seed 1.5–2.1 mm, papillate ..... E. clavatum

30' Plant loosely clumped, 1–5 dm; leaf 15–55 mm; fruit 40–100 mm

32. Pedicel in fruit 5–15 mm; fruit 40–65 mm; seed 0.9–1.2 mm, papillate; petals generally pink to rose-purple ..... E. hornemannii subsp. hornemannii

32' Pedicel in fruit 20–45 mm; fruit 50–100 mm; seed 1.1–1.6 mm, netted; petals generally white ..... E. lactiflorum

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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