Arenaria L.
Sandwort.
Caryophyllaceae, pink family.
Sp. Pl. 423. 1753.
Eremogone Fenzl, Verbreit. Alsin. 13, tab. ad 18. 1833.
(incl.)
Arenaria L. subgen. Eremogone (Fenzl) Fenzl
Vegetative morphology. Plants perennial herbs; 0.5–15 cm high. Taproot present, or absent. Caudex present, or absent. Ground-level or under-ground stems horizontal, or vertical and often branched; rhizomatous, or stoloniferous; elongate, or compact; 0.3–3(–7) mm wide. Aerial stems erect, or decumbent; glabrous. Leaves distributed along the stems, or in a basal tuft; opposite; marcescent. Petioles absent. Leaf blade bases cuneate, or attenuate. Blades 3–50 mm long; 0.5–2.5 mm wide. Blades appressed to the stem, or spreading; herbaceous, or somewhat fleshy; linear, or oblong, or lanceolate; flat, or folded; appearing single-veined, or with inconspicuous veins. Blades adaxial surface dull, or shiny; glabrous. Blades abaxial surface glabrous. Blade margins glabrous, or scabrous. Leaf apices acute, or mucronate.
Reproductive morphology. Flowering stems with leaves; glabrous, or hairy. Flowering stem hairs puberulent; simple; white or translucent. Flowers solitary, or in inflorescences. Inflorescence a dichasium. Flowers per inflorescence 1–6; small, less than 5 mm in diameter or length, or medium-sized, 5–15 mm in diameter or length. Calyx sepals 5; free; 3–6 mm long; 1–2.5 mm wide. Calyx green; herbaceous; glabrous. Petals free; same length as the calyx, or longer than the calyx; 5; white; obovate, or lanceolate; unlobed; 3.5–8 mm long. Stamens 10; filaments glabrous. Anthers yellow; ellipsoid, or ovoid; 0.2–0.8 mm long. Gynoecia superior. Carpels syncarpous; 3. Ovaries ovate, or oblong; glabrous. Styles 3; free; 0.8–2.5 mm long. Stigmas per style 1. Placentation free central. Ovules 10–35. Fruit with calyx persisting; dry; a capsule; elongate-cylindrical, or oblong; dehiscent; opening with teeth at the top of the capsule; teeth 6. Fruit 4–7 mm long; 2–3.5 mm wide; yellowish; surface appearing veinless. Seeds numerous; 0.6–1 mm long; brown; with surfaces verrucose.
Chromosome information. 2n = 22, 40 and 44 (in the eastern Canadian Arctic Archipelago, to 80 in Continental North American taxa).
Distribution. Northern hemisphere distribution: Greenland, Canada, United States, Eurasia.
Notes. Canadian authors, from Porsild (1957) to Scoggan (1978), have included Minuartia in a more widely circumscribed Arenaria. All or nearly all Eurasian authors (and Hultén for North America) have treated and treat Minuartia and Arenaria as separate genera. The present treatment follows Elven et al. (2002).
Illustrations. • Arenaria capillaris. Plant densely tufted from a stout, somewhat woody base. Photo used in exhibit 'Wildflowers of Mount Revelstoke National Park'. CMN, Photo-library, 577–769. • Arenaria humifusa. Plant with tufted or loosely matted stems from a subterranean creeping rhizome. Greenland, Godhavn (Osterdal), July 21, 1960. Photographed by Raymond Wood. CMN, Photo-library, 578–528.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
