Potamogeton fontigenus Y. H. Guo, S. C. Sun & H. Q. Wang; P. franchetii A. Bennett; P. longipetiolatus E. G. Camus; P. perversus A. Bennett.

Plants perennial, in fresh water. Rhizome terete, slender, with apical dormant buds. Stems terete, slender, 1.5-2 mm in diam., simple or rarely sparsely branched. Leaves dimorphic; stipules axillary, convolute, 2-7 cm, membranous, translucent, amplexicaul, often persistent, 11-19-veined; petiole 5-20 cm. Submerged leaves petiolate; blade narrowly lanceolate to lanceolate, herbaceous, often decaying early, 9-17-veined. Floating leaves petiolate; petiole 0.5-2.3 × length of blade; blade opaque, lanceolate to ovate-lanceolate or broadly elliptic, 2-10 × 1-4 cm, leathery, 11-19-veined, base obtuse or sometimes cuneate, apex acute or obtuse. Spikes cylindric, 2.5-8 cm, densely flowered, contiguous; peduncles thicker than stem, 3-10 cm. Carpels (1 or)2(or 3). Fruit broadly obovoid, 2.9-3.7 mm, abaxial keels 3, with a sharp midrib and ± obtuse lateral keels. Fl. and fr. May-Oct. 2n = 52.

The Chinese record of Potamogeton polygonifolius Pourret in FRPS (8: 67. 1992) was based on a misidentification of P. distinctus.

Ponds, paddy fields, channels. Fujian, Gansu, Guangdong, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [Bhutan, Indonesia, Japan (including Ryukyu Islands), Korea, Malaysia, Nepal, Philippines, Russia, Thailand, Vietnam; Pacific islands].