Artemisia palustris L.

Herbs, annual, 10-40 cm tall, much branched. Lower and middle stem leaves thin, ovate or elliptic-ovate, 2-5 × 1.5-3 cm, (1 or)2-pinnatisect; segments (2 or)3 or 4 pairs; lobules narrowly linear, 15-35 × 0.5-1 mm. Synflorescence a narrow panicle. Capitula in groups of 2-10 along branches. Involucre subglobose, 2-3 mm in diam. Marginal female florets 10-13. Disk florets 20-26, bisexual. Achenes ellipsoid. Fl. and fr. Aug-Nov. 2n = 18.