沼生苦苣菜 zhao sheng ku ju cai

Herbs to 1.8 m tall, perennial. Rhizome short, 4-5 cm thick. Stems stout, base ca. 3 cm in diam., branched apically. Lower stem leaves sessile, oblanceolate to lanceolate, 15-35 × 5-20 cm, undivided to pinnatipartite, glabrous, base sagittately clasping, margin denticulate, apex acuminate; lateral lobes if present 1-3 pairs, lanceolate, apex acute; terminal lobe triangular to triangular-lanceolate. Middle and upper stem leaves lanceolate; uppermost stem leaves reduced, linear-lanceolate to linear. Synflorescence corymbiform to paniculately corymbiform, with many capitula. Capitula with many (usually 70-90) florets; peduncle slender, densely glandular hairy. Involucre campanulate, to 1.5 cm. Phyllaries abaxially glandular hairy, apex acute to acuminate; outer phyllaries linear-lanceolate, 1-2 mm wide; inner phyllaries linear-lanceolate. Corolla ca. 1.2 cm. Achene narrowly ellipsoid, ca. 4 mm, weakly compressed, ± quadrangular in cross section, weakly rugose, between lateral ribs usually with 1 very strongly prominent main rib and several secondary ribs on either face. Pappus 7-8 mm, caducous ± as a unit. Fl. and fr. Jun-Sep. 2n = 18.

By water and lakes; 400-900 m. Xinjiang [Kazakhstan, Kyrgyzstan, W Russia, Tajikistan, Turkmenistan, Uzbekistan; Europe].