作者

Tang-Shui LIU and Chiu-Chen KUO

型態特徵

Aquatic annual or perennial herbs with submersed rhizomes and long petiole- like stems bearing a single floating leaf at the summit. Leaves petiolate, the lowermost ones rosulate, submerged, the higher ones solitary, floating, alternate or nearly opposite below the flowers, ovate or orbicular, deeply cordate at base, or rarely peltate with a closed sinus, the margins entire or slightly wavy, the lower surface with many convex dots (hydathodes). Flowers one to many, fascicled at the top of a petiole-like stem, ephemerous, actinomorphic, yellow or white, 5- merous; pedicels short or long; calyx deeply 5-parted nearly to base, the lobes oblong or lanceolate; corolla rotate or broadly campanulate, deeply 5-parted, hairy in the throat, the lobes induplicate-valvate in bud, entire or often fringed on margins or inside; stamens 5, inserted at base of the short corolla-tube, the filaments short, the anthers ovate to nearly linear; ovary ellipsoidal, often with 5 small glands alternating with the stamens at base, 1-celled, many-ovuled, the style short or longer, the stigma broad, mostly 2-lobed. Capsules ovoid or oblong, indehiscent or eventually rupturing irregularly; seeds haiiy or smooth, sometimes tubercled or winged along the margin.

參考文獻