Flora of the Canadian Arctic Archipelago
English: Field or prairie mouse-ear chickweed,
French: Céraiste à trois styles.
Caryophyllaceae, Pink family.
Published in Sp. Pl. 438. 1753.
Type: Sweden, Skåne, selected by Ugborogho, Phyton (Buenos Aires) 35: 177. 1977. Lectotype: LINN 603.9.
Vegetative morphology. Plants 4–30(–45) cm high; perennial herbs. Taproot present (slender). Ground level or underground stems horizontal; rhizomatous, or stoloniferous; elongate; 0.7–1 mm wide. Horizontal stems at ground level, branching extensively to shape plant habit as mats (or plants loosely caespitose). Caudex absent. Aerial stems decumbent. Aerial stem trichomes erect, or retrorse. Leaves distributed along the stems; opposite; marcescent (lower leaves with small axillary leafy shoots). Petioles absent. Leaf blade bases attenuate. Blades 5–20(–30) mm long, 1–5 mm wide, spreading, linear or lanceolate (narrowly), flat, appearing single-veined. Blade adaxial surface dull, glabrous or hairy, hairs short-silky (strigose), hairs simple, hairs sparse or moderately dense, hairs white, or translucent. Blade abaxial surface glabrous or hairy, hairs strigose, hairs sparse or moderately dense, hairs white. Blade margins with non-glandular hairs; apices acute.
Reproductive morphology. Flowering stems with leaves (and sterile shoots in the axils of the uppermost leaves). Flowering stems hairy. Flowering stems pubescent. Flowering stem hairs simple; white or translucent; glandular hairs present (in upper parts). 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 2–3.5(–5) mm long; 0.8–2(–3) mm wide; with a distinct scarious margin; margins 0.3–0.8 mm. Flowers per inflorescence 4–10(–20); medium-sized. Sepals conventional. Calyx base narrowly angled, or widely angled. Sepals 5; free; 1.5–2.5 mm long; 4.5–7.5 mm wide; green; herbaceous and scarious (0.25–0.5 mm broad, scarious margins). Calyx hairy. Calyx hairs pubescent; glandular and non-glandular; white or translucent. Petals conventional; free; longer than the calyx; 5; white; obtriangular; notched (the notch 0.2–0.3x the length of the petal); 7–10(–13) mm long; 3.5–6 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 20–50. Fruit with calyx persisting; dry; a capsule; elongate-cylindrical; straw-coloured; 6–8(–12) mm long; 2–3 mm wide; surface appearing veinless; mouth straight; dehiscent; opening with teeth at the top of the capsule; teeth 10. Seeds numerous; 0.7–1.2 mm long; brown (dark reddish); surfaces tuberculate.
Chromosome information. 2n = 36–38, ca. 64, 72, 90.
2n (2x) = 36-38. Taylor and Mulligan (1968, western Canada); Sokolovskaya (1970, northeastern and northern European Russia); Zhukova and Petrovsky (1971, Wrangel Island); Petrovsky and Zhukova (1981, Wrangel Island); Löve and Löve (1982, Canada). Numerous more southern counts have been reported, e.g., for the proposed subspecies of C. arvense in central Europe: subsp. glandulosum (Kit.) Soó (Favarger 1969, Boşcaiu et al. 1999) and subsp. strictum (Haenke) Gaudin (e.g., Söllner 1950, 1954);
2n = about 64. Dobes and Hahn (1997, central Europe);
2n (4x) = 72. Löve and Löve (1976b). Numerous more southern counts (e.g., Söllner 1950, 1954; Boşcaiu et al. 1999);
2n = 90. Ugborogho (1973, North America). Supposed basic chromosome number of family 9.
Ploidy levels recorded 8x, 4x.
Ecology and habitat. Substrates: cliffs, dry meadows; dry, moderately well-drained areas; gravel, sand, silt; with low organic content; acidic, or calcareous.
North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Rare. Boreal, alpine, Low Arctic. Arctic islands: Baffin.
Northern hemisphere distribution. Circumboreal. KaninPechora, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok (?), Kharaulakh, West Chukotka, East Chukotka, Central Canada, Labrador Hudson Bay, West Greenland.
General notes. Cerastium arvense is variable in growth habit, hairiness, leaf shape, and flower size. A number of subspecies have been distinguished, especially from central Europe. Two subspecies are recognised by Morton (2005) in the Flora of North America: subsp. arvense and subsp. strictum Gaudin [Fl. Helv. 3: 245. 1828]. According to Morton, subsp. strictum is a very variable, widely distributed taxon, which is difficult to circumscribe and to distinguish from the type subspecies. The two major ploidy levels (2x, 2n = 36, and 4x, 2n = 72) have been attached to the two entities 'arvense' s.s. and 'strictum' (Löve and Löve, in Löve 1975a), but correspondence between ploidy levels and the two subspecies accepted by Morton has not been fully established.
Illustrations. • Close-up of inflorescence. Inflorescence a dichasium. Note the small bract leaves with distinct scarious margins. Photograph by R. Borge. With permission of the Botanical Museum, University of Oslo, Norway. • Close-up of flower. Note the narrowly angled calyx base and the oblong, superior ovary with 5 free styles. Photograph by R. Borge. 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..