水蕴草属 shui yun cao shu

Herbs, perennial, freshwater. Rhizomes and stolons absent. Stems erect, rooted in substrate, branched or unbranched, elongate. Leaves cauline, in whorls of 5 or more, submersed, sessile; blade uniform in color throughout, linear, base sloping to stem, abaxial surface without prickles or aerenchyma, apex obtuse; midvein without rows of lacunae along sides; intravaginal squamules entire. Inflorescences 1-flowered, sessile; spathes not winged. Plants dioecious; flowers unisexual, projected to surface by slender, elongate floral tube base, pedicellate; petals white. Male flowers: filaments distinct; anthers linear; pollen in monads. Female flowers: ovary 1-locular; styles 3, not 2-fid. Fruit ovoid, smooth, dehiscing irregularly. Seeds fusiform, mucilaginous.

Three species: South America, introduced in Africa, Asia, Australia, Europe, and North America; one species (introduced) in China.

Lower Taxon

• Egeria densa Planchon