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 arcticum Lange

English: Arctic mouse-ear chickweed,

French: Céraiste arctique,

Inuktitut: Nunarait qakuqtat.

Caryophyllaceae, Pink family.

Published in Fl. Danica 17(50): 7, t. 2963. 1880.

Type: Greenland, Upernivik, leg. J.Vahl, selected by Hultén, Svenk Bot. Tidskr. 50: 459. 1956. Lectotype: UPS.

Synonymy. Cerastium nigrescens (H.C.Watson) Edmondston ex H.C.Watson subsp. arcticum (Lange) P.S. Lusby, in Brummitt et al. Watsonia 16: 295. 1987.

Cerastium arcticum Lange var. procerum (Lange) Hultén, Sv. Bot. Tidskr. 50: 451. 1956.

Cerastium arcticum Lange subsp. procerum (Lange) Hultén, Bot. Not. 130: 306. 1977.

Cerastium arcticum Lange var. vestitum Hultén, Sv. Bot. Tidskr. 50: 453. 1956.

Cerastium arcticum Lange var. sordidum Hultén (1956), Sv. Bot. Tidskr. 50: 456. 1956.

Cerastium hyperboreum Tolm., Skr. Svalb. Ishavet 34: 6. 1930.

Full synonymy in Brysting and Elven (2000).

Vegetative morphology. Plants 3–20(–30) cm high; perennial herbs. Taproot present (slender). Ground level or underground stems absent, or horizontal; rhizomatous; elongate; 0.7–1.5 mm wide. Caudex absent. Aerial stems decumbent. Aerial stem trichomes spreading, or erect. Leaves distributed along the stems; opposite; marcescent. Petioles absent. Leaf blade bases cuneate, or attenuate. Blades 7–20 mm long, 2–7.5 mm wide, spreading, elliptic (narrowly so) or oblanceolate, flat, appearing single-veined. Blade adaxial surface dull, hairy, hairs villous, hairs simple and glandular (0.9–3.6 mm long with 3–12 cells), hairs moderately 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 4–9 mm long; 2–6 mm wide; with a distinct scarious margin, or without a distinct scarious margin (rarely); margins less than 0.3 mm. Flowers per inflorescence 1–2 (-4); medium-sized. Sepals conventional. Calyx base widely angled, or rounded. Sepals 5; free; 1.6–3.1 mm long; 4–8(–9) mm wide; green, or green and purple; herbaceous and scarious (0.2–1.0 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 0.2x the length of the petal); 6.5–10 mm long; 3–6.5 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, or oblong; straw-coloured; 7–14 mm long; 3–5 mm wide; surface appearing veinless; mouth straight, or curved (slightly); dehiscent; opening with teeth at the top of the capsule; teeth 10. Seeds numerous; 0.8–1.2 mm long; brown (reddish); surfaces tuberculate.

Chromosome information. 2n = 108.

2n (3x) = 54. Böcher and Larsen (1950, Greenland, a single count);

2n (6x) = 108. Sørensen and Westergaard in Löve and Löve (1948, Greenland); Holmen (1952, Greenland); Jørgensen et al. (1958, Greenland); Engelskjøn (1979, Svalbard, 2n = 108–112); Brysting (2000, Greenland, Svalbard, and with references to previous reliable counts).

2n = about 130. Brysting (2000 southwestern Greenland, possibly an aneuploid number found in several plants in one population). Supposed basic chromosome number of family 9.

Ploidy levels recorded 12x.

Ecology and habitat. Substrates: hummocks, snow patches, river terraces, tundra, slopes, ridges; imperfectly drained moist areas, solifluction slopes, dry, moderately well-drained areas; rocks, gravel, sand, silt, clay; with low organic content; acidic, or calcareous, or nitrophilous.

North American distribution. Northwest Territories Islands, Nunavut Islands, continental Nunavut. Range in the Canadian Arctic Archipelago widespread. Common. High Arctic. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands (Melville Island), Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William, Southampton, Coats (Digges, Mill, Salisbury Islands and Melville Peninsula).

Northern hemisphere distribution. Amphi-Atlantic, or North American. Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. There are two 'competing' circumpolar treatments of the taxa within the polymorphic C. alpinum - C. arcticum complex. Hultén (1956) emphasised fairly recent hybridisation and introgression, whereas Böcher (1977) postulated a mature polyploid complex. Owing to the differing treatments and an assumed lack of diagnostic characters, many recent authors treating the Greenland and American plants have lumped all into an extremely widely defined C. alpinum.

Recent studies of the complex in the North Atlantic area confirm that the tetraploid (2n = 72) C. alpinum and the hexaploid (2n = 108) C. arcticum s.l. are closely related and that C. alpinum may be responsible for most of the genes in C. arcticum s.l. The latter is, however, morphologically and genetically heterogenous with a southern entity in Fennoscandia, the British Isles, Iceland, and possibly southwestern Greenland, and a northern entity in arctic European Russia, Svalbard, most of Greenland, and northeastern North America. According to Brysting and Elven (2000), these two entities should be recognised as two separate species: the name C. nigrescens (H.C. Watson) Edmondston, applied to the southern taxon (typified from Shetland); and C. arcticum s.s., to the northern taxon (typified from western Greenland). There are still some unresolved questions concerning southwestern Greenland material, which includes intermediate populations at a higher ploidy level (2n = about 132; Brysting 2000).

Both Hultén (1956) and Böcher (1977) proposed several new infraspecific taxa within C. arcticum. Hultén divided the arctic representatives into three varieties: var. procerum (Lange) Hultén, var. vestitum Hultén, and var. sordidum Hultén, whereas Böcher treated the variation he observed in arctic plants at the subspecific level as subsp. procerum (Lange) Böcher and subsp. hyperboreum (Tolm.) Böcher. Recent studies confirm that C. arcticum s.s. contains much morphological and genetical variation but do not support a further split into clearly definable geographical races or infraspecific taxa, as suggested by Hultén and Böcher (Brysting and Borgen 2000, Brysting and Elven 2000).

In western North America, C. arcticum is replaced by C. beeringianum, a species with which it tends to intergrade in eastern arctic areas.

Illustrations. • Habitat: Coral Harbour. Isolated densely cespitose plant growing in dry, calcareous gravel at a graveyard near the town. Nunavut, Salliq (Coral Harbour), 64░08'13"N, 83░09'53"W. Aiken and Brysting 01–080. CAN. Scale bar in cm. • Close-up of plant. Isolated densely cespitose plant growing in dry, calcareous gravel at a graveyard near the town. Nunavut, Salliq (Coral Harbour), 64░08'13"N, 83░09'53"W. Aiken and Brysting 01–080. CAN. Scale bar in cm. • Close-up of plant: Dorset. Plant growing at the edge of a snow patch indicated by Salix herbacea. Nunavut, Baffin Island, Cape Dorset. 4 August, 2005. Aiken. No voucher. Scale bar in cm. • Close-up of inflorescence. Inflorescence a dichasium. Large bract leaves without scarious margins. Nunavut, Salliq (Coral Harbour), graveyard near town on road to the airport, 64░08'13"N, 83░09'53"W. Aiken and Brysting 01–080. CAN. • Surface view of flowers. Flowers with translucent lines in the white petals. Baffin Island, Cape Dorset. 4 August, 2005. Aiken. No voucher. • Close-up of flower: side on. Calyx base widely angled or rounded. The whole plant is densely hairy with glandular and long non-glandular hairs. Nunavut, Salliq (Coral Harbour), graveyard near town on road to the airport, 64░08'13"N, 83░09'53"W. Aiken and Brysting 01–080. CAN. • Close-up of flower. Close-up of flower with 2-lobed petals (the notch 0.2–0.25x the length of the petal), 10 stamens and 5 styles. Nunavut, Salliq (Coral Harbour), graveyard near town on road to the airport, 64░08'13"N, 83░09'53"W. Aiken and Brysting 01–080. CAN. • Close-up of fruit. Capsule opening with a slightly curved mouth, 10 teeth and a persistent calyx. Nunavut, Salliq (Coral Harbour), graveyard near town on road to the airport, 64░08'13"N, 83░09'53"W. Aiken and Brysting 01–080. CAN. • Drawing of plant. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Dickson Land, Dickson Bay, Oxaas dal, below 567-toppen, fuglefjell [bird-cliff] below Karbonen, 400 msm. 10 August, 1924. J. Lid (not. O. A. H°eg as the drawing says, as C. alpinum, confirm). O 207856. With permission of the Botanical Museum, University of Oslo, Norway. • Drawing of plant. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Nathorst Land, Bellsund, below Louiseberget. 12 July, 1920. J. Lid 50 (as C. alpinum, confirm. A. Tolmatchew 1929, det. C. arcticum var. vestitum E. HultÚn 1955). O 207800. 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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