作者

YANG, YUEN-PO and LU, SHENG-YOU

型態特徵

Monoecious, submersed herbs without roots, freely suspended in water or anchored in soil in water by rhizoidal branches; stems slender. Leaves whorled, simple-linear or 2-4 times dichotomously divided into minutely serrulate filiform segments. Flowers solitary, axillary, actinomorphic; perianth thinly herbaceous, many-parted, narrow subvalvate segments connate at base, segments often dentate or lacerate at apex. Staminate flowers nearly sessile; stamens many, spirally arranged, maturing centripetally, filaments short, anthers 2-locular, dehiscing longitudinally, connective projecting apically, flanked by 2-several small denticles, thick, often colored. Pistillate flowers subsessile, 1-carpellate; ovary 1-locular; style terminal, terete, persistent; ovule 1, pendulous, orthotropous. Achenes ovoid or ellipsoid, smooth or warty, 1-spined apically; seed 1, ellipsoid, embryo large, straight.

屬

One genus with six species, cosmopolitan in fresh water.

參考文獻