Rotala hexandra Koehne

Herbs, annual, amphibious, to 40 cm. Stem ultimately erect, distinctly 4-winged. Leaves decussate, lanceolate to oblong, 1-3 cm, base cuneate to cordate or auriculate, apex obtuse. Bracts like foliage leaves; stipular growths present on nodes near leaf bases, to 2 mm. Flowers solitary, shortly pedicellate, axillary. Floral tube 6-merous, campanulate, ca. 2 mm, distinctly ribbed; sepals 6; epicalyx absent; bracteoles linear, less than 1/2 as long as floral tube. Petals 6, ca. 1 mm, surpassing sepals. Stamens 6, nearly free from tube at base of ovary; anthers exserted. Ovary globose, 4-loculed; style exserted. Capsule subglobose, ca. 1.5 mm in diam., slightly exserted, possibly irregularly dehiscent. Seeds 0.6-1 mm. Fl. and fr. Jul-Dec.

Hainan [Indonesia, Myanmar, Philippines].

Rotala kainantensis Masamune.