生活型

herb

形態特徵

• Annual erect herbs, rarely biennial, tap-rooted, stems terete, 30–120 cm tall, glabrous, sparsely branched or densely branching upward.
• Leaves grayish green, glabrous, smooth, linear to lanceolate, less than 1 cm wide, almost same width throughout, apex long attenuate to obtuse or rounded, sessile, subamplexicaul, margins entire, leaves on branches reduced, bract-like.
• Heads ca. 5–6 mm across, in loose racemose inflorescences, scattered or solitary on ascending branches or branchlets. Involucre subcylindric, 5–8 mm tall, 1.5–2 mm across, bracts 4 or 5 seriate, linear-lanceolate to subulate, acute, inner bracts gradually longer, herbaceous. Ray florets pistillate, numerous, ligules white or sometimes pale pink, 2–5 mm long, slightly exserted at anthesis. Disc florets yellow. Pappus longer than tubular part of floret at anthesis, elongate soon after anthesis, 5–6 mm long at maturity.
• Achenes cylindric, sparsely appressed short hairy, pale brown; pappus soft and fine.
• Chromosome number, 2n = 18 (Peng & Hsu, 1978).

物候

Flowering in autumn.

分布

• 台灣 : Now common on waste ground and roadsides in northern Taiwan.
• 世界 : Throughout the temperate northern hemisphere, introduced from North America and naturalized.

引證標本

TAIPEI: Nankang, Peng 11096, Peng 12155 & 13479. TAOYUAN: Lower Paling to Mt. Lalashan, Peng 12105; Tachi, Peng 13501. HSINCHU: Mt. Wuchihshan, Peng 12923 & 12129; Hukou, Peng 7226. MIAOLI: Yuanli, Peng 11115, Peng 11109.

參考文獻

• PENG, Ching-I & CHUNG, Kuo-Fang; LI, Hui-Lin, Flora of Taiwan, second edition 4: 861. 1998.  (Fl. Taiwan 2nd edit.)