Flora of the Canadian Arctic Archipelago
Onagraceae, Fireweed family.
Published in Herb. Raf. 5. 1833.
Synonymy. Epilobium L. subgen. Chamerion Raf., Amer. Monthly Mag. and Crit. Rev. 2: 266. 1818.
Chamaenerion Gray, nom. illeg., Nat. Arr. Brit. Pl. 2: 559. 1821. Non Ség., Pl. Veron. 3: 168. 1754. [= Epilobium L.].
Vegetative morphology. Plants 5–40 cm high; perennial herbs. Only fibrous roots present. Ground level or underground stems horizontal; rhizomatous (C. angustifolium); compact; 2–9 mm wide. Aerial stems developed; erect, or ascending, or decumbent. Aerial stem trichomes spreading, or retrorse. Leaves distributed along the stems; alternate, or opposite; dying annually and non-persistent. Petioles present (short), or absent; glabrous. Leaf blade bases obtuse, or cuneate. Blades (10–)25–75(–90) mm long, 1–15(–22) mm wide, spreading, linear or lanceolate, flat, veins pinnate or appearing single-veined. Blade adaxial surface glabrous. Blade margins glabrous; apices acuminate, or acute.
Reproductive morphology. Inflorescences racemose; elongating as the fruit matures. Pedicels with non-glandular hairs. Flowers per inflorescence 1–20; medium-sized. Sepals conventional; 4; free; 1.5–5.5 mm long; 4–18 mm wide; purple. Calyx glabrous, or hairy. Calyx hairs puberulent, or pubescent; non-glandular; white or translucent. Petals conventional; free; 4; white, or pink, or purple; obovate, or spatulate; unlobed; 10–25 mm long; 3–22 mm wide. Stamens 8; stamen filaments glabrous. Anthers purple; 1.4–2.2 mm long. Nectaries present. Ovary inferior; carpels 4; syncarpous. Ovaries hairy; puberulent, or pubescent. Ovary hairs very dense; white. Styles 4–12 mm long; straight; basal portion smooth, or with hairs at the base. Stigmas per ovary 4. Stigma lobes 2–5 mm long. Placentation axile. Ovules per ovary numerous and tiny. Fruit dry; a capsule; elongate-cylindrical; brown, or purple, or straw-coloured; 2–25 mm wide; hairy, or glabrescent; surface appearing veinless; not distinctly flattened; dehiscent. Seeds 0.8–2 mm long (sometimes with a tuft of yellowish hairs to 10 mm long); surfaces smooth.
General notes. Baum et al. (1994) published a phylogenetic analysis of Epilobium based on sequences of the ITS regions and the 5.8S cistron of nuclear ribosomal DNA. They found that section Chamaenerion (which includes our Chamerion [Epilobium] angustifolium and C. [E.] latifolium) was sister to the rest of the genus. Holub (1972) had previously argued that the nine species in this group were easily morphologically distinguishable and supported treating it as a separate genus. He presented evidence that the name Chamaenerion (although long used for this group) was illegitimate, and he published the new combinations with Chamerion.
Levin et al. (2003) discussed family-level relationship of Onagraceae based on chloroplast rbcl and NDHF data.
This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.
Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.
Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa..