Epilobium L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1981, Flora Europaea. Volume 2. Rosaceae to Umbelliferae, Cambridge University Press : 308-309

5. Epilobium L. 1

( Chamaenerion Séguier )

Perennial herbs, often flowering in the first year, overwintering by turions or rosettes, which persist about the base of the previous year’s stem, or by stolons. Leaves alternate, opposite, or verticillate. Flowers actinomorphic or weakly zygomorphic, small to medium-sized, in a leafy raceme or spike, or axillary; hypanthial tube short or absent. Sepals 4, erect; petals 4, white, pink or purple; stamens 8, in 2 whorls; stigma davate or capitate and entire, or deeply 4-lobed; ovary 4-locular. Fruit a long and slender, loculicidal capsule; seeds numerous, small, with a chalazal plume of hairs (coma).

Literature: C. Haussknecht, Monographie der Gattung Epilobium . Jena. 1884.

1 Leaves alternate; flowers showy, ± zygomorphic, the style deflexed, at least before the anthers have dehisced

2 Leaves lanceolate or elliptical; seeds smooth

3Inflorescence many-flowered; style 10-20 mm, becoming erect after the anthers have dehisced 1. angustifolium 3 Inflorescence few-flowered; style 4-7-5 mm, deflexed throughout anthesis 2. latifolium 2 Leaves linear or linear-lanceolate; seeds finely papillose

4 Leaves strigulose, at least along veins and on margins; style 7-15 mm, becoming erect after anthers have dehisced

3. dodonaei 4 Leaves glabrous; style 3-5-5 mm, deflexed throughout anthesis 4. fleischeri 1 Leaves opposite or verticillate, at least below; flowers actinomorphic, the style very rarely deflexed

5 Stigma distinctly 4-lobed

6 Stems patent-pubescent; leaves sessile or subsessile

7 Leaves semi-amplexicaul; petals usually more than 10 mm

5. hirsutum 7 Leaves not amplexicaul; petals less than 10 mm 6. parviflorum 6Stems appressed-pubescent or subglabrous; leaves mostly petiolate

8 Leaves narrowly cuneate at base; petiole 3-10 mm; petals white, later pink 10. lanceolatum 8 Leaves rounded at base; petiole usually less than 3 mm; petals pink to purplish

9 Overwintering by long, fleshy, hypogeal stolons up to 10cm; seeds 1-7—2 mm, attenuate, with a prominent beak 7. duriaei 9 Overwintering by turions or short, hypogeal stolons; seeds

c. 1 mm, without a beak

10 Leaves 3-5-8 x 1-4 cm; buds acute; petals 6-10 mm

8. montanum 10 Leaves 1-5 x 0-5-1-5 cm; buds obtuse; petals 3-6 mm

9. collinum 5 Stigma davate or capitate, not lobed

11 Stolons epigeal, filiform; leaves entire; seeds 1-5-2 mm, with a pellucid appendage 15. palustre

11 Stolons hypogeal or epigeal and leafy, or absent; leaves often toothed; seeds usually less than 1-5 mm, with or without appendage 12 Leaves usually verticillate; seeds 1•8-2 mm, with a pellucid appendage 11. alpestre 12 Leaves usually opposite; seeds 0-7-1-7 mm, with or without appendage 13 Plant creeping and rooting at the nodes 27. nerterioides 13 Plant not creeping and rooting at the nodes 14 Inflorescence, including ovary, ± conspicuously pubescent or strigulose

15 Inflorescence glandular

16 Seeds not striate-papillose, obovoid and rounded at ends 14. roseum

16 Seeds striate-papillose, acuminate with a pellucid appendage

17 Overwintering by turions; petals 5-6-5 mm, purplishpink 25. glandulosum

17 Overwintering by leafy rosettes; petals 2-5-6 mm,

purplish-pink or white 26. adenocaulon

15 Inflorescence entirely eglandular or with a few glandular hairs on the calyx only

18 Seeds with a pellucid appendage at apex (northern or montane plants)

19 Stigma capitate, held above the anthers at anthesis;

petals 5-5-7 mm 19. atlanticum

19 Stigma davate, surrounded by the anthers at anthesis; petals 3-6 mm

20 Stolons epigeal, leafy; leaves ovate or elliptical;

petals pale violet 17. nutans

20 Stolons absent; leaves linear to narrowly elliptical;

petals white, rarely pale pink 16. davuricum

18 Seeds without a pellucid appendage at apex

21 Stigma capitate; leaves with bulbils or short vegetative shoots in the axils; stems glandular

24. gemmascens

21 Stigma davate; leaves without bulbils or short vegetative shoots in the axils; stems eglandular

22 Stolons epigeal, leafy; calyx with a few erect, glandular hairs 13. obscurum

22 Stolons absent; calyx eglandular 12. tetragonum 14 Inflorescence, including ovary, subglabrous (small northern or montane plants)

23 Stolons epigeal, leafy, sometimes inconspicuous

24 Stolons short; petals white; inflorescence not or scarcely nodding before anthesis 22. lactiflorum

24 Stolons long; petals purplish-pink, more rarely white;

inflorescence nodding before anthesis

25 Leaves shortly petiolate; stem with weakly elevated lines decurrent from margins of petioles

20. anagallidifolium

25 Leaves sessile; stem with fine, not elevated lines decurrent from margins of petioles 18. tundrarum

23 Stolons hypogeal or absent

26 Strigulose lines decurrent from margins of petioles not elevated; petals white, rarely pink 16. davuricum

26 Strigulose or smooth lines decurrent from margins of petioles elevated; petals violet or purplish to white

27 Petals 2-5-4 mm, white; seeds c. 1-2 mm 22. lactiflorum

27 Petals 4-11 mm, violet or purplish; seeds c. 1 mm

28 Petals 4-6 mm, violet; seeds finely papillose

21. homemannii

28 Petals 7-11 mm, bright purplish-pink; seeds smooth

23. alsinifolium