Monoecious, caulescent. Stems 15-60 cm, ramified. Leaves sessile, semi-amplexicaulous, 2-5 cm by 1-1.5 mm; midrib connected by very minute cross-veins with the margin; at the leaf base 2 minute axillary, elliptic squamulae intravaginales. Spathe axillary, sessile, 1-flowered, 1.5-2.5 cm; tips obtuse. Flowers bisexual. Sepals linear-lanceolate, acute, 1-nerved, pale green, 3-3.5 by 1 mm. Petals 1-nerved, silvery white, 5.5-7 by 0.75 mm. Stamens 3; filaments 2-2.5 mm; anthers linear to linear-lanceolate, 0.75-1 mm. Ovary 1.5-2 cm, rostrum 2.5-3 cm; styles 2-2.5 mm. Fruit linear-lanceolate, 1.5-2 cm. Seeds 10-20, fusiform, at the ends very acute, 1.5-2 mm; testa with 3-6 longitudinal rows of more or less blunt spines, connected by minute scarious membranes.
Rare lowland species, but locally not uncommon, e.g. in the southern part of the Malay Peninsula and Singapore. It forms thick masses in muddy ponds and ditches and may be a pest, growing with great rapidity, often together with Hydrilla verticillata, but by its pale green colour it is rapidly distinguished, according to DUNSEL-MAN, who found it common in ditches near Pontianak. Self-fertilization often occurs, because the stigmas are frequently covered with pollen grains already in bud. Fl. fr. Jan.-Dec.
Home