Cerastium arvense L.
Field or Prairie Mouse-ear Chickweed.
Sp. Pl. 438. 1753.
Type: Sweden, Skåne, Linnaean Herbarium 603.9 (LINN) lectotype, selected by Ugborogho, Phyton (Buenos Aires) 35: 177. 1977.
Vegetative morphology. Plants 4–30(–45) cm high; matted or loosely cespitose. Taproot present (slender). Caudex absent. Ground-level or under-ground stems horizontal; rhizomatous, or stoloniferous; elongate; 0.7–1 mm wide. Aerial stems decumbent; densely hairy (glandular hairs in upper parts); stem hairs erect, or reflexed. Leaves distributed along the stems. Leaf blade bases attenuate. Blades 5–20(–30) mm long; 1–5 mm wide. Blades spreading; herbaceous; linear, or lanceolate (narrowly); flat; appearing single-veined. Blades adaxial surface dull; glabrous, or hairy. Blades adaxial surface hairs short-silky (strigose); simple, unbranched; sparse, or moderately dense; white and translucent. Blades abaxial surface glabrous, or hairy. Blades abaxial surface hairs sparse, or moderately dense. Blades abaxial surface strigose. Blades abaxial surface hairs white, or translucent hairs. Blade margins with non-glandular hairs. Leaf apices acute.
Reproductive morphology. Flowering stems hairy. Flowering stem hairs pubescent. Flowering stems glandular hairs present (in upper parts). Flowering stem hairs white or translucent. Flowers in inflorescences, or solitary. Inflorescence a dichasium; main branches angle of divergence less than 30 degrees, or 30–60 degrees. Pedicels 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, 5–15 mm in diameter or length. Calyx base narrowly angled, or widely angled. Calyx sepals 5; free; 4.5–7.5 mm long; 1.5–2.5 mm wide. Calyx green; herbaceous and scarious (0.25–0.5 mm broad, scarious margins); hairy; pubescent. Calyx hairs glandular and non-glandular; white or translucent. Petals longer than the calyx; 5; white; obtriangular; shallowly lobed (the notch 0.2–0.3x the length of the petal); 7–10(–13) mm long; 3.5–6 mm wide. Stamens 10. Anthers yellow; ellipsoid; 0.6–0.9 mm long. Carpels 5. Ovaries oblong. Styles 5; 2–3 mm long. Ovules 20–50. Fruit elongate-cylindrical; mouth straight; teeth 10. Fruit 6–8(–12) mm long; 2–3 mm wide; straw coloured. Seeds 0.7–1.2 mm long; brown (dark reddish); with surfaces tuberculate.
Chromosome information. 2n = 72 (and 36). 36-38
(2x). - Taylor and Mulligan (1968 western Canada); Sokolovskaya (1970
north easternorthern 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; Boscaiu et al. 1999)
and subsp. strictum (Haenke) Gaudin (e.g. Söllner 1950, 1954).
c.64. - Dobes and Hahn (1997 Central Europe).
72 (4x). -
Löve and Löve (1976b). Numerous more southern counts (e.g.
Söllner 1950, 1954; Boscaiu et al. 1999).
90. - Ugborogho (1973
North America). Supposed basic chromosome number of family 9. Ploidy levels
recorded 8x, 4x.
Distribution. Northern hemisphere distribution: circumpolar and circumboreal; Greenland, St. Pierre and Miquelon, Canada, United States, Eurasia. Alaska, Yukon, Continental Northwest Territories, Nunavut Islands, Northern Québec. Boreal, or alpine, or low arctic. Range in the Canadian Arctic Archipelago limited. Rare. Arctic Islands: Baffin.
Ecology and habitat. Substrates: cliffs, dry meadows; dry, or moderately well drained areas; acidic, or calcareous; gravel, sand, silt; with low organic content.
Notes. 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 in the developing Flora North America (Morton, pers. communication 2002): 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 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 with 3–10 flowers; small bract leaves with a distinct scarious margin. Photo by R. Borge. With permission of the Botanical Museum, University of Oslo, Norway. • Close-up of flower. Calyx base narrowly angled; oblong ovary with 5 free styles. Photo by R. Borge. With permission of the Botanical Museum, University of Oslo, Norway. • Distribution map.
Cite this publication as: ‘A.K. Brysting, P.J. Scott, and S.G. Aiken 2001 onwards. Caryophyllaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000) , and Aiken, Dallwitz et al. (1999) should also be cited (see References).
