13. Potamogeton lucens Linnaeus, Sp. Pl. 1: 126. 1753.
光叶眼子菜 guang ye yan zi cai
Potamogeton gaudichaudii Chamisso & Schlechtendal; P. sinicus Migo.
Plants perennial, submerged in fresh water. Rhizome slender to robust. Stems terete, elongated, ca. 2 mm in diam., richly or sparsely branched. Stipules axillary, large, conspicuous, convolute, 2-8(-11) cm, herbaceous, free from leaf base; leaves subsessile to shortly petiolate; petiole 2-15 mm; leaf blade elliptic or ovate-elliptic to lanceolate-elliptic, 2-18 × 0.8-5 cm, 9-11-veined, midvein thickened and conspicuous, without rows of lacunae bordering midvein, base cuneate, margin often undulate, minutely denticulate, apex mucronate or cuspidate. Spikes densely flowered, with many whorls of somewhat opposite flowers; peduncles 3-20 cm, thickened upward. Carpels 4. Fruit ovoid, 3.2-4.5 mm, abaxial keel distinct; beak short. Fl. and fr. Jun-Oct. 2n = 52.
Lakes, ponds, channels. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jiangxi, Jilin, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Xinjiang, Xizang, Yunnan [Afghanistan, India, Kazakhstan, Kyrgyzstan, Myanmar, Nepal, Pakistan, Philippines, Russia, Tajikistan, Turkmenistan, Uzbekistan; N Africa, SW Asia, Europe].