生活型

herb

形態特徵

• Annual herbs. Stems erect, grayish green, 50–150 cm tall, branching upward or sometimes not, hirsute pubescent.
• Basal and lower leaves withered but persistent at anthesis, lower and middle cauline leaves oblanceolate to lanceolate, 4–10 cm long, 0.5–1.5 cm wide, apex acute, base attenuate, margins generally few toothed apically or subentire; upper leaves smaller, linear to lanceolate, subentire, pubescent on both surfaces.
• Heads numerous, in large panicles, 3–5 mm long, 5–8 mm across, pedunculate. Involucre urceolate, bracts 3-seriate, linear lanceolate, acute, sparsely hirsute, outer ones shorter, 2–3 mm long, inner ones ca. 5 mm long, margins scarious. Ray florets many, in 3 or 4 rows, filiform-tubular, ligules minute, obscure, 3–4 mm long, nearly equalling pappus, yellowish. Disc florets 5–10, corolla narrowly tubular, ca. 5 mm long, gradually opening upward, 5-lobed, yellowish.
• Achenes oblong-oblanceolate, 0.7–1.5 mm long, 0.3–0.4 mm wide, compressed, ribbed on both sides, minutely pubescent, pale umber. Pappus tawny, capillary, bristles 1-seriate, 5 mm long at maturity, persistent. Flowering year round in Taiwan.
• Chromosome number, 2n = 54 (Peng & Hsu, 1978).

物候

Flowering year round in Taiwan.

分布

• 台灣 : very common in open, waste fields and construction sites from lowlands to 2,000 m.
• 世界 : A pantropical weed of South American origin, early established in Sumatra.

引證標本

TAIPEI: Taipei City, Peng 6045. TAOYUAN: Yungan Port, Peng 12769; Hsiayun-Hsiayunping, Peng 10279. MIAOLI: Yuanli, Peng 11111. TAICHUNG: Wuling, Peng 11059. NANTOU: Chingjing Farm, Peng 6090; Lulin Lodge to Tatachia Saddle, Peng 11444. HUALIEN: Kuanyuan, Peng 9194; Tayuling, Peng 13135.

參考文獻

• PENG, Ching-I & CHUNG, Kuo-Fang; LI, Hui-Lin, Flora of Taiwan, second edition 4: 919. 1998.  (Fl. Taiwan 2nd edit.)