Shrub 0.5-3 m, entirely villous, the hairs often multicellular, especially in the inflorescence; Leaves lanceolate to broadly lanceolate, 4-12 by 0.3-1.5 cm, narrowly cuneate at base, apex acute to acuminate; Flowers in upper leaf axils. Sepals 4 or 5, lanceolate, irregularly serrulate, 10-18 by 4-8 mm, villous. Petals bright yellow, veiny, suborbicular, 15-24 by 16-26 mm, shallowly emarginate, with a claw 1-3 mm. Stamens 8 or 10, subequal; Capsule villous, 1.2-3 by 0.6-1 cm, light yellowish brown with 4 prominent dark brown ribs, 4-angled, thin-walled, readily and irregularly loculicidal; Seeds pluriseriate in each cell, free, light brown, finely striate and cellular pitted, obovoid, 0.6-0.8 mm long;
Asia-Tropical: Jawa (Jawa present); Malaya present; Sumatera (Sumatera present), New World, SE. United States, South America
Native of the New World, from the SE. United States throughout South America, introduced and naturalized in Malesia since the 2nd half of the last century, collected in Malaya, Sumatra, Java (common in West), but obviously still absent from many areas.
BACKER () observed that in inundated situation the plant produces aerophores which are emitted by shallow, horizontal roots; they are erect but their tips usually float on the water.
Ridl. 1922 – In: Fl.Mal. Pen.: 828
BACK. 1914 – In: Trop. Natuur: 61
ALSTON 1931 – In: Trimen, Fl. Ceyl. 6
BACK. 1909: Ann. Jard. Bot. Btzg: 406
Munz 1942 – In: Darwiniana: 131
Steen. 1949: Fl. Sch. Indon.: 305
LINNE 1930: Onkr. Suiker: 470: Atlas t. 445
RAVEN 1963: p. 345. – In: Reinwardtia: map 14