细叶满江红 xi ye man jiang hong

Azolla japonica Franchet & Savatier; A. pinnata R. Brown var. japonica (Franchet & Savatier) Franchet & Savatier.

Plants more robust than Azolla imbricata. Lateral branches axillary, numbers of lateral branches less than fronds of stem; when in shallow water or wet places or plants in crowded situations, stems becoming erect and dorsal lobes changing to ventral ones. Sporangium with 3 floats on exospore; massulae of microsporangium covered with anchorlike hairs.

Cultivated and escaped, rice fields, ponds, ditches. Widely distributed in the Chang Jiang valley, also in S China, including Taiwan [Japan; NE Asia, Europe, North and South America, Pacific islands].

The whole plant of Azolla filiculoides is used as green manure and forage.