21. Artemisia annua Linnaeus, Sp. Pl. 847. 1753; DC., Prodr. 6: 119. 1837; Boiss., Fl Or. 3: 371. 1875; Hook. f., Fl. Brit. Ind. 3: 323. 1881; Pamp. in Nuov. Giorn. Bot. Ital. n. s. 34: 637. 1927; Kitam., Fl. Afghan. 386. 1960; R.R.Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 715. 1972; Cullen in P.H.Davis, Fl. Turk. 5: 317. 1975; Tsiang & Li, Icon. Corm. Sin. 4: 530. fig. 6473. 1975; Gutterman in Tutin et al., Fl. Europ. 4: 185. 1976; Podlech, l. c. 175. t. 60. 1986.
A.wadei Edgew. in Trans. Linn. Soc. 20: 72. 1846; A. stewartii C.B.Clarke, Comp. Ind. 163. 1876.
Erect, annual herb with up to 1.5 m tall, sparsely puberulous, striate, red-tinged, simple stem. Basal and lower stem leaves long petiolate, ovate, 3-pinnatisect, 3 – 10 x 2 – 5 cm, primary segments remote, oblong,, pinnatisect or pinnatipartite, secondary segments pinnatifid into lanceolate, 1 – 5 x 0.5 – 1 mm, acute, entire or toothed lobules; upper and mid stem leaves subsessile or sessile, (1-) bipinnatisect, basally auriculate, uppermost in floral region lanceolate, dentate or linear and entire. Capitula heterogamous, pedunculate, numerous, hemispherical, remote, 1.5 – 2 x 2 – 3 mm, nodding in lax, 10 – 50 x 5 – 20 cm, terminal panicle with oblique or patent branches. Involucre 3-seriate, phyllaries glabrous, shining; outermost linear-oblong, green with narrow scarious margins, inner oblong-ovate or broadly ovate-elliptic, with broad scarious margins. Receptacle conical, glabrous. Florets up 30, greenish-yellow, all fertile; marginal florets 5-10, with irregularly 2-toothed, filiform, glandulose corolla tube; disc-florets 5-20, bisexual, with broadly tubular, 5-dentate, c. 1 mm long corolla. Cypselas narrowly oblanceolate, 0.6 – 0.8 mm long, brown.
Fl. Per.: August-September.
Type: Describe from Siberia, Herb. Linn. 988.33 (LINN).
Distribution: Central & South Europe, Turkey, S. Russia, Palestine, Syria, Iran, Afghanistan, Pakistan, India and South China; introduced and naturalised in Canada and U. S. A.
