互花狐尾藻 hu hua hu wei zao

Plants mostly monoecious, rarely with bisexual flowers. Perennating turions absent. Stem few branched, 50-100 cm, sparsely brown oval warty, densely leafy, shoot tips knoblike with crowded leaves; internodes 5-10 mm. Submerged leaves 4- or 5-whorled, pectinate, broadly lanceolate in outline, 1-4 × 0.5-1.2 cm; segments in 8-10 pairs, filiform, 0.5-1.5 cm. Inflorescence a terminal spike, nodding before flowering, to 3-7(-12) cm; bracts ovate or linear, margin entire to serrate. Male flowers alternate; bracteoles shorter than flower; calyx campanulate, ca. 0.3 mm, apex 3-toothed; petals yellow, red streaked, oblong-obovate, 1.5-2 mm, 5-6 × as long as calyx; stamens 8. Female flowers opposite or whorled; bracteoles longer than flowers; calyx campanulate, 0.7-1 mm, apex 3-toothed. Fruit 4-loculed, subcylindric, 1.5-2 × ca. 1.5 mm; mericarps sparsely verrucose. 2n = 14. Fl. and fr. Apr-Sep.

Stagnant waters, lakes; 500-1500 m. Anhui, Gansu, Hubei, Jiangsu [Russia; C Asia, Europe, North America (Alaska, NE United States)].