生活型

herb

形態特徵

• Stems 25–85 cm tall, erect, tetragonous, slightly puberulous on upper part, branched.
• Median cauline leaves opposite, 11–19 cm long, more of less pubescent on both surfaces (petioles 3.5–5 cm long, wingless), bipinnatipartite, lower segments often 2- or 3-cleft or pinnatifid, terminal segments narrow, acuminate, few-dentate; upper leaves gradually smaller, uppermost alternate, small, pinnati-partite.
• Heads 6–10 mm broad; peduncles 1.8–8.5 cm long. Involucre cupuliform, bracts 5–7, lanceolate, 2.5 mm long to 5 mm long in fruit, linear-oblong, apex obtuse or acute, outer palea oblong, 3.5–4 mm long, to 6–8 mm long in fruit, obtuse, inner ones narrowly obtuse, 5 mm long to 12 mm long in fruit. Ray florets 1–3, yellow, 5–6 mm long. Disc florets fertile, corolla yellow, tubular, 4.5 mm long, 5-lobed.
• Achenes long linear, 10–12×1 mm, 3- or 4-angular, more or less short strigose. Pappus awns 3 or 4, 3–4 mm long.
• Chromosome number, 2n = 72 (Peng & Hsu, 1978).

分布

• 台灣 : usually in the south, along roadside and in waste grounds.
• 世界 : Probably native of eastern United States and eastern Asia, naturalized in South America, Australia, South Asia and Europe.

引證標本

HSINCHU: Chupei, Lienhuassu, Peng 8589. PINGTUNG: Kenting Natl. Park, Sheting, Peng 12511; Kenting Park, Peng 12574.

參考文獻

• PENG, Ching-I & CHUNG, Kuo-Fang; LI, Hui-Lin, Flora of Taiwan, second edition 4: 868. 1998.  (Fl. Taiwan 2nd edit.)