Spergula
Sp. Pl. 1: 440. 1753.
Gen. Pl. ed. 5, 199. 1754.
Taxon | Illustrator ⠉ | |
---|---|---|
Drymaria molluginea Spergula arvensis Drymaria cordata var. cordata | Barbara Alongi Barbara Alongi Barbara Alongi |
Herbs, annual or winter-annual. Taproots slender to ± stout, especially proximally. Stems spreading or ascending to erect, simple or branched, terete to somewhat angular. Leaves opposite but appearing whorled, as 8–15 per axillary cluster, 2 clusters per node, connate proximally by often-prominent ridge from which stipules arise, sessile; stipules 4 per node, white, ovate to triangular, margins entire but splitting variously with age, apex obtuse to acuminate; blade 1-veined, linear or filiform, sometimes succulent, apex blunt to apiculate. Inflorescences terminal, open to diffuse cymes; bracts paired, minute. Pedicels erect to ascending, spreading or usually reflexed and sometimes secund in fruit. Flowers usually bisexual, sometimes pistillate by stamen abortion; perianth and androecium briefly perigynous; hypanthium dish or cupshaped, not abruptly expanded distally; sepals distinct, silvery, elliptic to nearly ovate, 2.5–5 mm, herbaceous, margins scarious, apex acute to obtuse; petals 5, white, blade apex entire; nectaries at adaxial base of broader filaments opposite sepals; stamens 5 and opposite sepals, or 10 and arising from distally tapered rim of hypanthium; filaments distinct; styles 5, distinct, filiform, 0.4–0.6 mm, glabrous proximally; stigmas 5, linear along adaxial surface of styles, obscurely papillate (30×). Capsules ovoid, opening by 5 spreading to somewhat recurved valves; carpophore absent. Seeds 5–25, blackish, circular, subglobose or lenticular and laterally compressed, nearly smooth or finely papillate, membranous, entire marginal wing often present, appendage absent; embryo peripheral, annular to spirally curved. x = 9.
Distribution
Introduced; Eurasia (esp. Mediterranean region), Eurasia (Europe)
Discussion
Species 5 (3 in the flora).
Spergula arvensis is the only species of the genus that has been introduced extensively outside of Eurasia.
Selected References
None.
Lower Taxa
Key
1 | Leaf blades usually appearing terete, 1.5-3(-5) cm, margins often revolute, forming abaxial channel; seeds subglobose, sometimes with keel or wing ± 0.1 mm wide | Spergula arvensis |
1 | Leaf blades usually flat, 0.3-1.5(-2) cm, usually not channeled abaxially; seeds lenticular, laterally compressed, wings 0.2-0.6 mm wide | > 2 |
2 | Seed wings light brown to brownish black, 0.2-0.3 mm wide; stamens usually 10 | Spergula morisonii |
2 | Seed wings white or sometimes slightly tannish, 0.4-0.6 mm wide; stamens usually 5 | Spergula pentandra |