1. Sium suave Walter, Fl. Carol. 115. 1788.
泽芹 ze qin
Apium cicutifolium (Schrenk) Bentham & Hooker ex Forbes & Hemsley; Cicuta dahurica Fischer ex Schultz; Sium cicutifolium Schrenk; S. formosanum Hayata; S. nipponicum Maximowicz.
Plants 60–120 cm, stout. Root fibrous or fascicled, fusiform. Leaf blade oblong or ovate, 6–25 × 7–10 cm; pinnae 3–9 pairs; leaflets lanceolate or linear, 10–40 × 3–15 mm, margin serrate. Upper leaves smaller, 3-lobed or entire, sessile on expanded sheaths. Umbels 4–8 cm across, terminal on stem and branches; bracts 6–10, lanceolate or linear-lanceolate, 3–15 mm, entire or incised; rays (8–)10–20, 1.5–3 cm, unequal; bracteoles 5–10, linear-lanceolate, 1–3 mm, entire; umbellules 10–20-flowered; pedicels 3–5 mm. Calyx teeth triangular-lanceolate or minute triangular, 0.5–2 mm. Fruit ovoid, ca. 3 × 2 mm, ribs prominent, corky, thickened, narrowly winged; vittae 1–3 in each furrow, 2–6 on commissure. Fl. Jul–Aug, fr. Sep–Oct.
Damp grasslands, marshlands, streamsides. Hebei, Heilongjiang, Jilin, Liaoning, Nei Mongol, Ningxia, Shandong, Taiwan [Japan, Korea, Russia; North America].
This species has reputed medicinal value. Sium ninsi Thunberg (Fl. Jap. 118. 1784), known from Korea, Japan, and SE Russia, is likely to occur also in SE Heilongjiang and E Jilin. The upper part of the plant is morphologically similar to S. suave but can be distinguished by the long-petiolate, ternate uppermost cauline leaves (vs. sessile in S. suave).