by Nathaniel Lord Britton & Addison Brown

“ Leaves alternate or the uppermost opposite, often of 2 kinds, submerged and floating, the submerged mostly linear, the floating coriaceous, lanceolate, ovate or oval. Spathes stipular, often ligulate, free or connate with the base of the leaf or petiole, enclosing the young buds and usually soon perishing after expanding. Peduncles axillary, usually emersed. Flowers small, spicate, green or red. Perianth none. Stamens 4. Anthers sessile, the connective dilated, perianth-like (Fig. 186) . ”

“ Floating leaves thick, the blade ovate, oval or elliptic, 2'-4' long, 1'-2' wide, usually tipped with a short abrupt point, rounded or subcordate at the base, many-nerved; submerged leaves reduced to phyllodes or bladeless petioles which commonly perish early and are seldom seen at the fruiting period ”

“ Floating leaves oval or ovate, abruptly pointed at the apex, rounded at the base, 2'-4' long, 11⁄4'-2' wide, many-nerved; petioles 3'-5' long; submerged leaves mostly petioled, the uppermost often elliptic or oval, 3'-6' long, 1'-21⁄2' wide, the lowest lanceolate, often 8' long, with the sides closed and assuming a falcate shape; stipules tapering to a long sharp point, sometimes 4' long; peduncles thickened upward, 2'-8' long; spikes cylindric, 1'-2' long; fruit 2"-21⁄2" long, 11⁄4" thick, turgid, the pericarp hard, obliquely obovoid, 3-keeled; face more or less angled; style subapical ”