Sagina L.
Pearlwort.
Caryophyllaceae, pink family.
Sp. Pl. 128. 1753.
Spergella Rchb.
Vegetative morphology. Plants perennial herbs; 1–10 cm high; vegetatively proliferating by bulbils or fragmentation, or not vegetatively proliferating by bulbils or fragmentation. Taproot present. Caudex absent. Ground-level or under-ground stems horizontal, or not developed horizontally or vertically; stoloniferous; elongate, or compact; 0.5–1.2 mm wide. Aerial stems erect, or decumbent; glabrous, or sparsely hairy; stem hairs spreading, or erect. Leaves distributed along the stems, or basal in a rosette; opposite; marcescent. Petioles absent. Leaf blade bases cuneate. Blades (2–)4–12(–25) mm long; 0.3–1.2 mm wide. Blades spreading; herbaceous; linear; flat, or folded; with inconspicuous veins. Blades adaxial surface dull; glabrous. Blades abaxial surface glabrous. Blade margins glabrous. Leaf apices acuminate, or acute, or mucronate.
Reproductive morphology. Plants bisexual, or bisexual and agamospermic. Flowering stems with leaves; glabrous, or hairy. Flowering stem hairs pubescent; simple. Flowering stems glandular hairs present. Flowering stem hairs white or translucent. Flowers solitary, or in inflorescences. Inflorescence a dichasium. Flowers per inflorescence 1–3; small, less than 5 mm in diameter or length, or medium-sized, 5–15 mm in diameter or length. Calyx sepals 5, or 4; free; 1.4–3.5(–4) mm long. Calyx green, or green and purple; herbaceous, or herbaceous and scarious; glabrous, or hairy. Calyx hairs glandular; white or translucent (if applicable). Petals free; same length as the calyx, or longer than the calyx; 4, or 5; white; obovate, or lanceolate; unlobed; 1.4–6 mm long. Stamens 10, or 8–10; filaments glabrous. Anthers yellow; ellipsoid, or ovoid; 0.2–1 mm long. Gynoecia superior. Carpels syncarpous; 4, or 5. Ovaries ovate; glabrous. Styles 4, or 5; free; 0.4–3.5 mm long. Stigmas per style 1. Placentation free central. Ovules 8–25. Fruit with calyx persisting; dry; a capsule; ovoid; dehiscent; opening with teeth at the top of the capsule (splitting almost to the base); teeth 5 (usually, or 4). Fruit 2–4.5 mm long; 1.5–3 mm wide; golden brown, or straw coloured; surface appearing veinless. Seeds several; (0.4–)0.5–1 mm long; brown; with surfaces verrucose.
Chromosome information. 2n = 52, 56, 70–74, 77.
Distribution. Northern hemisphere distribution: circumpolar, or circumboreal; Greenland, Canada, United States, Eurasia.
Illustrations. • Sagina cespitosa. Plant forming small, rather compact, hemispherical tufts, 1–9 cm in diameter. Norway. Photo by R. Elven. • Sagina nivalis. Plant in fruit, growing in disturbed ground at the edge of a road; flowering stems radiating from the base of a central rosette. Nunavut, Rankin Inlet, near the graveyard, 62°48'N, 92°06'W. Aiken and Brysting 01–046. CAN. • Sagina nodosa subsp. borealis. Flowering plant growing in dry, sun baked dolomite gravel. Manitoba, Churchill, Beech Bay, in the tidal estuary of the Churchill River, south of the Port, 58°44.30'N, 94°08.06'W. Aiken and Brysting 01–032. CAN.
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).
