1. Ludwigia perennis Linn., Sp. Pl. 119. 1753; excl. verbis erroneis "foliis oppositis"; Raven, Reinwardtia 6: 367. 1963; Raven in Rech. f., Fl. Iran. 7: 2. 1964; Raven in Fl. Taiwan 897. 1977; Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 508. 1972.
Peter C. Hoch and Peter H. Raven
Ludwigia parviflora Roxb., Hort. Beng. 11. 1814 (nomen); Fl. Ind. 1: 440. 1820; Boiss., Fl. Or. 2: 752. 1872; Clarke in Hook. f., Fl. Brit. Ind. 2: 588. 1879. Jussiaea perennis (Linn.) Brenan, Kew Bull. 8: 163. 1953.
Annual herb up to 1 m tall, subglabrous or minutely puberulent on younger parts. Leaves narrowly elliptical to lanceolate, 1-11 x 0.3-2.7 cm, narrowly cuneate at base, the apex subacute, with petioles 2-15 mm long, winged. Sepals 4(-rarely 5), deltoid, 2-3.5 x 0.7-1.8 mm, glabrous or minutely puberulent. Petals yellow, elliptical, 1-3 x 0.7-2 mm. Stamens as many as sepals, rarely more. Pollen shed in tetrads. Style 0.7-1.5 mm long. Capsules thin-valled, glabrous or puberulent, 3-16(-19) mm long, terete, readily and irregularly loculicidal, sessile or on a pedicel up to 6 mm long, often more or less nodding. Seeds pluriseriate in each locule of the capsule, free, brown with fine brown lines, ellipsoid-rounded, 0.3-0.5 x 0.2-0.25 mm, with narrow, inconspicuous raphe. Gametic chromosome number, n = 8.
Lectotype: Sri Lanka ("Ceylon"), Hermann (BM; designated by Brenan, Fl. Trop. E. Afr., Onagr. 13. 1953).
Distribution: Africa, tropical and subtropical Asia, China, through Malesia to tropical Australia and New Caledonia. Rare in Pakistan, in wet places, from sea level to 1000 m. Fl. Per.: Jul-Aug.
