Herbs, freshwater. Stems usually cormlike. Leaves all basal, petiolate, usually sheathing at base; blades submerged or sometimes floating, linear to broadly ovate, 3-11-veined. Spathes elliptic or ovate, usually 2-6-winged, apex bifid or trifid, with 1 to many flowers. Flowers bisexual or unisexual and plants dioecious. Male flowers with longer pedicel. Bisexual and female flowers shortly pedicellate or without pedicel. Sepals 3, greenish, linear, oblong, or ovate. Petals 3, colored, orbicular to broadly obovate, much longer and wider than sepals. Stamens 3-15; filaments linear, flattened; anthers laterally dehiscent; staminodes (absent or 1-)3, often present in female flowers. Ovary of 3, 6, or 9 (or more) carpels; ovules numerous; stigmas 2 per style, linear. Fruit cylindric, fusiform, or conic. Seeds numerous, small, often hairy.
Plants annual or perennial, of fresh waters. Rhizomes and stolons absent [present]. Erect stems rooted in substrate, unbranched, short. Leaves basal, submersed [floating], petiolate; blade lanceolate to reniform [linear], base cuneate to cordate, apex rounded to acute; midvein without rows of lacunae along sides, blade uniform in color throughout; abaxial surface without prickles or aerenchyma, smooth; intravaginal squamules entire. Inflorescences scapose, long-pedunculate; spathes winged or ribbed. Flowers bisexual [unisexual, staminate and pistillate on different plants], sessile [staminate pedicellate], floating or occasionally opening under water; petals white to pink or light violet, often yellow at base; filaments distinct; pollen in monads; ovary 1-locular; styles 3--9, not 2-fid. Fruits oblong, ridged, dehiscing irregularly. Seeds fusiform, covered with hairs.
Nectaries ± 3, located at the base of the styles, lobe-like, ± 1 mm. long
Ovary of 3–20 or more carpels, narrowly cylindric, ellipsoid or ovoid, 1-locular, placentation parietal; ovules numerous, anatropous; perianth-tube narrowly cylindric or cylindric; styles 3–20 or more; stigmas 6–40 or more, 2 per style, linear, papillose.
Monoecious, dioecious or hermaphrodite, submerged, freshwater, annual or perennial herbs
Leaves distichous to spirodistichous, radical, often showing marked differentiation into juvenile and mature leaves; juvenile leaves sessile, linear to ovate, obovate or spathulate, sometimes armed with spines or thorn-like projections; mature leaves often petiolate, sheathing at the base; leaf-blade submerged, partly emergent or floating, elliptic to orbicular, acuminate to obtuse, or rounded, cuneate, obtuse, rounded, cordate or involute at base, smooth or scabrid, with up to 15 prominent longitudinal veins connected by cross-veins; margins green, entire, denticulate, undulate or crispate
Stamens 3–15 or more, in whorls of 3, anthers erect, 4-?theecous, latrorsely dehiscent; filaments often somewhat flattened and fleshy, smooth, papillose or ciliate.
Stems corm-like, simple or forked or (not in East Africa) rarely elongate, rhizomatous and irregularly branched
Petals 3, ovate to orbicular or obovate, truncate, rounded or obcordate, usually clawed at base.
Sepals 3, narrowly lanceolate to ovate, acute to rounded, often persistent in fruit.
Fruit fleshy, cylindrical to ovoid, opening by decay of the pericarp or by regular dehiscence
Seeds numerous, narrowly cylindric to ellipsoid, sometimes with a short apical projection; testa membranous, densely covered with unicellular hairs.
Male flowers pedicellate, remaining attached to the plant at anthesis; ♀ and hermaphrodite flowers sessile or subsessile
Spathe solitary in leaf-axil, membranous or coriaceous, subsessile or pedunculate, the peduncle often spirally contracting after anthesis in ♀ and ♂ flowers, submergent to emergent, often inflated, narrowly cylindric to ovoid, with wings, ribs, spines, warts or thorns, rarely smooth, 2–6-lobed at the apex, with 1–40 flowers
Cook, C. D. K., J.-J. Symoens, and K. Urmi-König. 1984. A revision of the genus Ottelia (Hydrocharitaceae). I1. Generic considerations. Aquatic Bot. 18: 263--274. Cook, C. D. K. and K. Urmi-König. 1984. A revision of the genus Ottelia (Hydrocharitaceae). 2. The species of Eurasia, Australasia, and America. Aquatic Bot. 20: 131--177. Holmes, W. C. 1978. Range extension for Ottelia alismoides (L.) Pers. (Hydrocharitaceae). Castanea 43: 193--194. Turner, C. E. 1980. Ottelia alismoides (L.) Pers. (Hydrocharitaceae) — U.S.A., California. Madroño 27: 177.
|[Malay am ottelambel, apparently from otta, to stick to, in reference to thin leaves that stick to body, and am bel, nymphaea]|