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

Cerastium alpinum L.

English: Alpine mouse-ear chickweed,

French: Céraiste alpin.

Caryophyllaceae, Pink family.

Published in Sp. Pl. 438. 1753.

Type: Selected by Jonsell and Jarvis, Nord. J. Bot. 14: 156. 1994. Lectotype: LAPP 192.

Vegetative morphology. Plants 5–20(–35) cm high; perennial herbs. Taproot present (slender). Ground level or underground stems horizontal; rhizomatous; elongate; 0.7–1.5 mm wide. Horizontal stems at ground level, branching extensively to shape plant habit as mats. Caudex absent. Aerial stems ascending, or decumbent. Aerial stem trichomes spreading, or erect. Leaves present; distributed along the stems; opposite; marcescent. Petioles absent. Leaf blade bases cuneate, or attenuate. Blades 7–21 mm long, 2–6 mm wide, spreading, elliptic (sometimes narrowly so) or oblanceolate or spatulate (nearly), flat, appearing single-veined. Blade adaxial surface dull, hairy, hairs villous, hairs simple and glandular (1.6–4 mm long with 6–20 cells, intermixed with thinner and shorter hairs less than 0.3 mm long), hairs moderately dense or dense, hairs white, or translucent. Blade abaxial surface hairy, hairs villous, hairs moderately dense or very dense, hairs white. Blade margins with non-glandular hairs and with glandular hairs; apices acute, or obtuse (more rarely).

Reproductive morphology. Flowering stems two or more per plant; with leaves. Flowering stems hairy. Flowering stems villous. Flowering stem hairs simple; white or translucent; glandular hairs present. Flowers in inflorescences (very rarely solitary). Inflorescences with flowers in a dichasium. Inflorescence main branches angle of divergence less than 30˚, or 30–60˚. Bract leaves 2.5–3(–5) mm long; 0.9–3 mm wide; with a distinct scarious margin (or with only scarious apices, rarely); margins 0.3–0.8 mm. Flowers per inflorescence (1–)2–4(–7); medium-sized. Sepals conventional. Calyx base narrowly angled. Sepals 5; free; 1.5–3 mm long; 4–9 mm wide; green; herbaceous and scarious (0.2–0.9 mm broad, scarious margins). Calyx hairy. Calyx hairs villous; glandular and non-glandular; white or translucent. Petals conventional; free; longer than the calyx; 5; white; obtriangular; notched (the notch approximately 0.2 × the length of the petal); 9–15 mm long; 4–7 mm wide. Stamens 10; stamen filaments glabrous. Anthers yellow; ellipsoid; 0.6–0.9 mm long. Ovary superior; carpels 5; syncarpous. Ovaries oblong; glabrous. Styles 5; free; 2–3 mm long. Stigmas per ovary 1. Placentation free central. Ovules per ovary 25–50. Fruit with calyx persisting; dry; a capsule; elongate-cylindrical; straw-coloured; 7–16 mm long; 2–4 mm wide; surface appearing veinless; mouth curved; dehiscent; opening with teeth at the top of the capsule; teeth 10. Seeds numerous; 1–1.3 mm long; brown (reddish); surfaces tuberculate.

Chromosome information. 2n = 72.

2n = 72 from about 83 to 144. From all parts of its distribution area, e.g., Böcher and Larsen (1950, Greenland); Söllner (1950, 1952, 1954, central Europe); Hedberg (1967, Canada); Böcher (1977, Iceland); Engelskjøn (1979, Norway); Jørgensen et al. (1958, Greenland); Löve and Löve (1982, northern Canada: Churchill).

2n = 83 ± 8 and 2n = 98 ± 4. Mosquin and Hayley (1966, northern Canada);

2n = about 144. Brett (1951, northern Sweden);

For more chromosome references see Brysting (2000), Elven et al. (2003). Supposed basic chromosome number of family 9.

Ploidy levels recorded 8x.

Ecology and habitat. Substrates: slopes, ridges, cliffs; dry, moderately well-drained areas; rocks, gravel, sand; with low organic content; acidic, or calcareous, or nitrophilous.

North American distribution. Nunavut Islands, continental Nunavut, northern Quebec, Labrador (subsp. lanatum), Newfoundland (var. glanduliferum and subsp. lanatum). Range in the Canadian Arctic Archipelago limited. Common. Arctic (mainly low arctic). Arctic islands: Baffin, Southampton (Mill Island and Melville Peninsula).

Northern hemisphere distribution. Amphi-Atlantic. Northern Iceland, Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. Three subspecies of C. alpinum are recognised from European parts of the North Atlantic area: subsp. alpinum, subsp. lanatum (Lam.) Graebn. and Correns, and subsp. glabratum (Hartman) Á. and D. Löve. This subdivision is mainly based on differences in pubescence, although other distinguishing characters (growth form and leaf shape) as well as different ecological preferences also have been indicated. Densely lanate plants are included in subsp. lanatum, whereas glabrous or nearly glabrous plants are included in subsp. glabratum. In some treatments, glabrous plants have been given specific rank as C. glabratum Hartman (e.g., Hultén 1955, 1956, Jalas et al. 1993). Densely lanate forms were originally described as a separate species, C. lanatum, by Lamarck (1785). Recent studies based on hybridisation experiments, analyses of habitat choice, morphometric, and isoenzyme analyses support the prevailing Nordic view of three subspecific taxa of equal rank (Grundt et al. 1999, Brysting and Borgen 2000).

Cerastium alpinum from Greenland and other Arctic areas has been referred to subsp. lanatum by several authors (e.g., Hultén 1956). This subspecies was, however, described from central Europe and has a relatively thermophilous, montane to low alpine distribution in central Europe and Fennoscandia. The arctic representatives differ from the central and northern European subsp. lanatum in several morphological characters (they are generally coarser, have long, narrow, and more acute leaves, larger flowers and fruits, and a coarser indumentum). The lanate plants of Arctic areas have probably evolved independently of the thermophilous plant of central and northern Europe, and the subspecific name should be avoided for arctic populations (Elven and Elvebakk 1996). The arctic (Greenland, North American) plants may merit rank as a fourth and yet unnamed subspecies (Elven et al. 2003).

Even though much variation in hairiness is found in North American plants of C. alpinum, there seems to be little support for a split into clearly definable geographical races or subspecies within the North American area at this time.

Illustrations. • Close-up of plant. Isolated flowering stem. Leaves opposite, small, slightly fleshy, and glabrous Nunavut, Baffin Island, Ogac Lake. 12 July, 2004. Aiken and LeBlanc 04–073. CAN 586541. • Close-up of stem. Small pedicel bract leaves with a distinct scarious margin. The whole plant is densely hairy with glandular and non-glandular hairs. Nunavut, Rankin Inlet, 6248'N, 9206'W. Aiken and Brysting 01–052. CAN. • Close-up of leaf. Leaves densely hairy with glandular and long non-glandular hairs. Manitoba, Churchill, Northern Studies Centre, 5844'N, 9349'W. Aiken and Brysting 01–015. CAN. • Close-up of inflorescence. Inflorescence a dichasium. This inflorescence is in fruit. Manitoba, Churchill, Northern Studies Centre, 5844'N, 9349'W. Aiken and Brysting 01–015. CAN. • Close-up of flower. Calyx base narrowly angled. The petals are longer than the sepals and 2-lobed (the notch 0.2–0.25x the length of the petal). Nunavut, Rankin Inlet, 6248'N, 9206'W. Aiken and Brysting 01–052. CAN. • Surface view of flower. Note sepals with whitish margins at the apex, deeply cleft petals, small anthers and 3 free styles with long stigmatic surfaces. Aiken and LeBlanc 04–073. CAN 586541. • Side view of flower. Note glandular hairs on the reddish free sepals and the deeply cleft obovate white petals. Aiken and LeBlanc 04–073. CAN 586541. • Close-up of fruit. Elongate-cylindrical, straw-coloured capsule with a curved mouth. Manitoba, Churchill, Northern Studies Centre, 5844'N, 9349'W. Aiken and Brysting 01–015. CAN. • Close-up of fruit. Capsule opening with 10 teeth and a curved mouth. Note the persistent calyx. Manitoba, Churchill, Northern Studies Centre, 5844'N, 9349'W. Aiken and Brysting 01–015. CAN. • 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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