Flora of the Canadian Arctic Archipelago
English: Tufted pearlwort,
French: Sagine cespiteuse.
Caryophyllaceae, Pink family.
Published in Rink, Grønland 2: 133. 1857.
Type: Greenland, leg. Vahl, selected by Crow, Rhodora 80: 57. 1978. Lectotype: C.
Synonymy. Arenaria caespitosa J.Vahl, Fl. Dan., 39: 13, t. 2289. 1840.
Spergella caespitosa (J.Vahl) Á. Löve and D. Löve, Bot. Not. 128: 508. 1976.
Vegetative morphology. Plants 1–2.5(–4.5) cm high; perennial herbs; caespitose. Taproot present. Ground level or underground stems horizontal, or absent; stoloniferous; compact; 0.5–1.2 mm wide. Horizontal stems at ground level, branching extensively to shape plant habit as cushions (or cushion-like, forming small, flat or depressed, usually reddish green tufts, one to a few centimetres in diameter, dominated by one central leafy rosette). Caudex absent. Aerial stems erect, or decumbent. Aerial stem trichomes spreading, or erect. Leaves distributed along the stems; opposite; marcescent. Petioles absent. Leaf blade bases cuneate. Blades (2–)4–6(–8) mm long, 0.6–1 mm wide, spreading, linear, folded, with inconspicuous veins. Blade adaxial surface dull, glabrous. Blade abaxial surface glabrous. Blade margins glabrous; apices acuminate.
Reproductive morphology. Flowering stems two or more per plant; with leaves (1–3 pairs). Flowering stems hairy. Flowering stems pubescent. Flowering stem hairs simple; white or translucent; glandular hairs present. Flowers solitary. Flowers small. Sepals conventional; 5; free; 2.5–3.5(–4) mm wide; green and purple; herbaceous, or herbaceous and scarious. Calyx hairy, or glabrous. Calyx hairs glandular; white or translucent. Petals conventional; free; longer than the calyx (slightly); 5; white; obovate; unlobed; 2.5–3.5(–4) mm long. Stamens 10; stamen filaments glabrous. Anthers yellow; ellipsoid; 0.2–0.3 mm long. Ovary superior; carpels 5; syncarpous. Ovaries ovate; glabrous. Styles present; 5; free; 0.5–0.8 mm long. Stigmas per ovary 1. Placentation free central. Ovules per ovary 10–20. Fruit with calyx persisting; dry; a capsule; ovoid; golden brown; 2.5–3.9 mm long; 2.5–3 mm wide; surface appearing veinless; dehiscent; opening with teeth at the top of the capsule (splitting almost to the base); teeth 5. Seeds several; 0.5–1 mm long; brown; surfaces verrucose.
Chromosome information. 2n = 84 and 88.
2n = 84. Löve and Löve, in Löve (1975a, northern Iceland); Löve and Löve (1982, Arctic Canada);
2n = 88. Knaben, in Löve and Löve (1948, Norway); Knaben (1950, Norway); Löve and Löve (1956, Iceland).
Ecology and habitat. Substrates: along streams, lakeshores (beaches), ridges; imperfectly drained moist areas, seepage slopes, moderately well-drained areas; gravel, sand, moss; with low organic content, with high organic content; calcareous, or nitrophilous. In wet sands and gravels of shorelines and stream margins, wet mossy places, and dry rocky barrens and gravelly hillocks.
North American distribution. Northeast Arctic, south to northern Manitoba, James Bay and northern Labrador. Amphi-Atlantic. Nunavut Islands, continental Nunavut, northern Quebec, Labrador, Newfoundland. Range in the Canadian Arctic Archipelago limited. Uncommon. Low Arctic. Arctic islands: Baffin, Victoria, Southampton.
Northern hemisphere distribution. Amphi-Atlantic. Northern Iceland, Northern Fennoscandian, Svalbard Franz Joseph Land, Central Canada, Labrador Hudson Bay, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. Crow (1978) stated that the plants from North America and western Greenland differ from European plants of this taxon in having glandular trichomes on the upper portion of the pedicels and on the base of the calyx. While European plants are totally glabrous, the amount of glandular pubescence in the North American material is variable. Sparsely glandular pubescent plants are frequent, and occasionally glabrous specimens are encountered. Among the glandular pubescent plants examined, on average 70% of the pedicels exhibited glandular pubescence, while 30% of the pedicels of the same plants were glabrous. Crow (1978) concluded that separate nomenclatural recognition of European and North American material seemed unnecessary.
Illustrations. • Close-up of plant. Plant forming small, rather compact, hemispherical tufts that are 1–9 cm in diameter. Norway. Photograph by R. Elven. • 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..