4. Oenanthe linearis Wallich ex de Candolle, Prodr. 4: 138. 1830.
线叶水芹 xian ye shui qin
Plants 30–70 cm. Roots fibrous or fusiform. Stems decumbent, rooting at lower nodes, unbranched or few-branched above. Leaves heteromorphic, lower petioles 1–10 cm; blade triangular-ovate, 3–7 × 2–5 cm, mostly 1-pinnate, rarely 2-pinnate; ultimate segments linear, 20–40 × 1–2 mm, rarely rhombic-ovate or lanceolate, 5–30 × 2–5 mm. Upper leaves sessile, 1-pinnate; pinnae linear, 10–40 × 1–3 mm. Umbels 2–4(–5) cm across, often leaf-opposed; peduncles 2–10 cm; bracts absent, or 1, linear; rays 3–12, 1.5–3 cm, unequal; bracteoles 3–8, linear or linear-lanceolate, 3–6 mm, unequal; umbellules 8–20-flowered; pedicels 1.5–4 mm. Calyx teeth ca. 0.5 mm. Styles ca. 2 mm, reflexed. Fruit ovoid, ca. 2 × 1.5 mm; dorsal and intermediate ribs filiform. Fl. May–Jul, fr. Jul–Aug.
Open forests, Moist shade under shrubs and trees, grassy valley slopes, marshlands, grassy places near water; 800–3000 m. Chongqing, Guizhou, Hubei, Sichuan, Taiwan, Xizang, Yunnan [India, Indonesia, ?Laos, Myanmar, Nepal, Vietnam].
Some authors consider both varieties conspecific with Oenanthe javanica (see the taxonomic note under that species).