5. Bidens radiata Thuillier, Fl. Env. Paris, ed. 2. 432. 1799.
大羽叶鬼针草 da yu ye gui zhen cao
Bidens radiata var. microcephala C. H. An.
Annuals. Stems (5-)15-60(-80) cm tall, erect, branched, in upper part simple, glabrous or indistinctly hairy. Leaves yellowish green, 3-5-parted or dissected, lateral parts lanceolate or ovate-rhombic, serrate-toothed, apical part much larger than laterals, glabrous or subglabrous, on rather long petiolules, sometimes entire, large toothed to parted (Bidens radiata f. pseudocernua Ganeschin). Capitula discoid, erect, 12-15(-20) mm wide, wider than long (sometimes almost 2 ×); calycular bracts narrowly linear, exceeding in length or equal to achenes (including awns); outer phyllaries (9 or)10-12(-14), oblong-linear or lanceolate-linear, 8-20 mm, leaflike, margin with fine prickles, considerably exceeding florets (sometimes almost 3 ×), inner shorter, oval. Florets tubular. Achenes cuneate, 3-4 mm, glabrous, compressed, with 2 awns, equal to or almost shorter than achenes, sometimes awns 4, but then 2 longer than other 2. Fl. Jun-Sep.
Riverbanks, lakes, marshes, wet meadows, wet ditches. Heilongjiang, Jilin, Nei Mongol, Xinjiang [Japan, Korea, Mongolia, Russia; Europe].