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

Luzula wahlenbergii Rupr.

English: Wahlenberg's wood rush,

French: Luzule de Wahlenberg,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Juncaceae, Rush family.

Published in Beitr. Pfl. Russ. Reich. 2: 58. 1845.

Synonymy. Luzula spadicea (All.) var. wahlenbergii (Rupr.) Buchenau, in Engler, Das Pflanzenreich, 25 (4, 36): 63. 1906.

Vegetative morphology. Plants 15–35 cm high; perennial herbs; caespitose (loosely). Only fibrous roots present. Ground level or underground stems horizontal (not always present on specimens), or vertical; compact (when horizontal). Aerial stems erect. Leaves mainly basal; alternate; marcescent. Petioles absent. Sheaths present; with trichomes (throat pilose, accutely angled). Ligules absent. Leaves grass-like. Blades 50–100 mm long, 2.5–6(–8) mm wide, straight, linear, flat or involute (at the tips), veins parallel. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blade margins with non-glandular hairs (simple, unbranched, glabrescent); apices acuminate.

Reproductive morphology. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems with leaves (1–5 cm long). Leaf or reduced bract subtending the base of the inflorescence present; reduced, or scale-like; shorter than the apex of the inflorescence (10 mm long or less; bracteoles brown, margins with long curly cilia). Inflorescences paniculate, or cymose (also described as sub-cymose, or anthelate, few flowered; main branches generally 2–4, spreading less than 90°, lax, usually arching); diffuse (flowers solitary on short pedicels); 3–8 cm long. Inflorescence primary branches 10–50 mm long; with spreading secondary branches. Pedicels present. Individual spike(s) erect, or ascending, or pendent. Floral bracts apices lacerate. Flowers per inflorescence 20–50; small. Sepals conventional (brown tepals); 3; free; 2–2.5 mm wide (margins finely lacerate towards the apex); brown, or purple (tinged); scarious. Calyx glabrous. Petals conventional (brown tepals); free; same length as the calyx; 3; brown; lanceolate; unlobed; 1.9–2.1 mm long. Stamens 6. Anthers 0.5–0.7 mm long. Ovary superior; carpels 3; syncarpous. Styles 1; free. Stigmas per ovary 3. Ovules per ovary 3. Fruit sessile; with calyx persisting; dry; a capsule; ovoid; brown; 2.3–2.5 mm long; 1–1.3 mm wide (intact capsules); not distinctly flattened; dehiscent. Seeds 3; 1–1.3(–1.6) mm long; brown (a dark reddish brown); surfaces smooth.

Chromosome information. 2n (4x) = 24. Nordenskiöld (1951, 1953b); Holmen and Mathiesen (1953, Greenland); Zhukova (1966, 1967a, northeastern Asia); Hedberg (1967, northern Canada); Knaben and Engelskjøn (1967, northern Norway); Knaben (1968, Alaska); Johnson and Packer (1968, northwestern Alaska); Zhukova and Tikhonova (1973, Chukotka); Zhukova and Petrovsky (1976, western Chukotka); Yurtsev and Zhukova (1978, eastern Chukotka); Löve (1981d, central Canada); Zhukova (1982, northeastern Asia).

A deviating chromosome count of 2n = 36 from northern Sweden (Löve and Löve, 1944a) was not included by Löve and Löve (1975) and is therefore discounted. It is probably belongs to the L. arcuata group (Elven et al. 2003).

Ploidy levels recorded 4x.

Ecology and habitat. Substrates: wet meadows, snow patches (occasionally), along streams, lakeshores, slopes (boggy); imperfectly drained moist areas, seepage slopes (and "slump areas"); sand, silt, moss; acidic (usually, or neutral substrates, reported on granite, and in sphagnum bogs). Throughout the species' range, L. wahlenbergii is typically found in tundra sphagnum bogs and in moss by brooks or lakeshores; wet slopes below snowbeds; in low wet Arctagrostis meadows; among large boulders on sandy silt near a Puccinellia phryganodes meadow (CAN 520296). A Low Arctic plant, the northernmost record in Canada occurs on Baffin Island, at Pangnirtung.

North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec. Range in the Canadian Arctic Archipelago limited. Common (where it occurs). Low Arctic. Arctic islands: Baffin.

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, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, East Greenland.

General notes. The only location for this taxon in Greenland (northeast) could be explained by migration from the Eurasian Arctic (Yurtsev, personal communication, 2001).

Illustrations. • Habitat: Baffin Island. Reddish brown plants of Luzula wahlenbergii in mid-zone of photograph. Nunavut, Baffin Island, Iqaluit, wet meadow of Sylvia Grinnell Park near the river. 25 August, 1997. Aiken 97–032. CAN. • Habitat: Baffin Island. Plants to 30 cm high. Nunavut, Baffin Island, Iqaluit, Sylvia Grinnell Park. 1 August, 2005. Aiken 05–066. CAN. 586938. Same zone of plants as previous image, but taken earlier in season in a different year. • Inflorescence silhouette. Inflorescence paniculate or sub-cymose with few flowers borne towards the ends of the nodding branches. Nunavut, Baffin Island, Iqaluit. Aiken 05–066. CAN. 586938. Photograph by Kathy Thornhill. • Close-up of developing capsules. Capsules with brown tepals. Note bracts below tepals and pedicel. S. Aiken 05–066. CAN 586938. • Close-up of flowers. Note purplish brown tepals that taper to long acuminate lacerate tips. Bracts subtend the tepals and pedicels. Nunavut, Baffin Island, Iqaluit. Aiken 05–066. CAN. 586938. Photograph by Kathy Thornhill. • 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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