Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Eutrema edwardsii R. Br.

English: Edwards' eutrema,

Inuktitut: Eutréma d'Edwards.

Brassicaceae (Cruciferae), Draba family.

Published in Chlor. Melvill. 9. 1823.

Synonymy. Eutrema labradoricum Turcz. Bull. Soc. Nat. Mosc. 27.(2), 305. 1854.

Vegetative morphology. Plants 8–30 cm high; herbs; perennial herbs. Taproot present. Ground level or underground stems absent. Caudex present. Aerial stems erect. Leaves distributed along the stems; alternate; dying annually and non-persistent. Petioles present, or absent; 30–40 mm long (twice to several times longer than blade). Leaf blades simple. Leaf blade bases obtuse, or attenuate. Blades 9–35 mm long, 4–25 mm wide, lanceolate (or narrowly ovate), veins pinnate or appearing single-veined. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blades not lobed. Blade margins entire, glabrous. Hydathodes absent. Blade apices acute.

Reproductive morphology. Flowering stems with leaves. Inflorescences racemose; elongating as the fruit matures. Flowers per inflorescence 6–14(–20); small; radially symmetrical (actinomorphic). Sepals conventional; 4; free; 1–1.3 mm long; 1.5–2.3 mm wide; purple; herbaceous. Calyx glabrous. Petals conventional; free; 4; white; without contrasting markings; obovate; slightly lobed or undulating; 3.2–4.5 mm long; 1.3–1.7 mm wide. Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous; free of the corolla. Anthers yellow; 0.4–0.5 mm long. Ovary superior; carpels 2; syncarpous. Ovaries glabrous. Styles 1; 0.3–0.4 mm long. Stigmas per ovary 1. Placentation parietal. Ovules per ovary 8–12. Fruit stalk 3–4 mm long; dry; a silique; elongate-cylindrical (compressed parallel to septum, septum perforate); purple; 12–17 mm long; 1.5–2 mm wide; glabrous; dehiscent; shedding the outer walls to expose a thin inner wall, with the seeds attached at the margins on either side. Styles persisting in fruit 0.5–0.6 mm long. Seeds 8–12; 1.6–1.8 mm long; brown; surfaces verrucose.

Chromosome information. 2n = 28, 42, and 56.

2n (4x) = 28. Böcher and Larsen (1950, Greenland); Holmen (1952, Greenland); Mulligan (1964, North America); Zhukova (1966, northeastern Asia); Hedberg (1967, northern Canada); Johnson and Packer (1968, northwestern Alaska); Packer and McPherson (1974, northern Alaska); Löve and Löve (1982, Arctic Canada); Yurtsev and Zhukova (1982, northern Siberia); Zhukova and Petrovsky (1984, northern and northeastern Asia); [Numeri Chromos. Fl. URSS 1990, eastern Siberia]; Mulligan (2003);

2n (6x) = 42. Sokolovskaya and Strelkova (1941, 1960, northern Russia); Mulligan (1964); Packer (1964, northern Canada); Zhukova et al. (1977, northeastern Asia); Zhukova and Petrovsky 1984, northern and northeastern Asia; [Numeri Chromos. Fl. URSS 1990, northwestern and northern Siberia];

2n (8x) = 56. Knaben (1968, central Alaska).

Ploidy levels recorded 4x, 6x,and 8x.

Ecology and habitat. Substrates: wet meadows, around the margins of ponds, along streams, river terraces, lakeshores (beaches), ridges; imperfectly drained moist areas, seepage slopes, solifluction slopes, dry; gravel, sand, silt, clay; with low organic content, with high organic content; calcareous, or nitrophilous.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago widespread. Common. Arctic. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg (Digges), Parry islands (Melville, Prince Patrick), Cornwallis, Banks, Victoria, Prince of Wales, King William, Southampton.

Northern hemisphere distribution. Circumpolar. Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. Elven et al. (2003) noted that the growth form of this species varies depending upon the habitat. The infructescences are characteristically narrow, much elongated, and with the siliques widely spaced. From the Nordic experience, it is difficult to recognise the Alaskan plants as the same species. The wide morphological variation, and also the ploidy variation, indicates some structure that might be recognisable taxonomically (Elven, in Elven et al. 2003).

Illustrations. • Habitat: Baffin. Plants with white flowering heads growing in dense moss. Nunavut, Baffin Island, Iqaluit. Aiken and Mallory 02–006. CAN. Scale bar in cm. • Plant growing beside rock: Baffin, Iqaluit. Plant about 10 cm tall, growing beside the marker, in the shelter of a rock. Nunavut, Baffin Island, Iqaluit, Sylvia Grinnell Park. 1 August, 2005. Aiken 05–071. CAN 586943. • Close-up of plant. Plant about 10 cm tall, growing beside the marker, in the shelter of a rock. Nunavut, Baffin Island, Iqaluit, Sylvia Grinnell Park. 1 August, 2005. Aiken 05–071. CAN 586943. • Habitat. Isolated plant growing in cryptogamic mat between rocks. Nunavut, Baffin Island, Cape Dorset. 3 August, 2005. Aiken. No voucher. • Close-up of plant. Plants with simple entire glabrous leaves and a small cluster of white flowers. Nunavut, Baffin Island, Iqaluit. Aiken and Mallory 02–067. CAN. • Surface view of flower. A flower with four white petals, 6 dehisced anthers, and purple-red developing siliques. Note sessile, capitate stigmas. Aiken and Mallory 02–010. CAN. • Plant setting fruits: Dorset. Plant about 15 cm high with inflorescence elongating as fruit develops. Nunavut, Baffin Island, Cape Dorset. 7 August, 2005. Aiken. No voucher. Scale bar in cm. • Close-up of flower and fruiting body. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Dickson Land, Dickson Bay, Oxaas dal. 26 August, 1924. J. Lid. O 201285. With permission of the Botanical Museum, University of Oslo, Norway. • Arctic Island Distribution.


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.

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