生活型

herb

形態特徵

• Annual or biennial herbs. Stems erect, solid, 30–130 cm tall, sparsely pilose, much branched from middle, branches strongly ascending, further ramifying and forming an open corymbiform panicle.
• Leaves alternate, scarcely pilose on both surfaces, sometimes nearly glabrous, often ciliate with short hairs; radical leaves forming large rosette, ovate to oblong-lanceolate, 3–7 cm×1.5–4 cm, margins dentate; petiole 5–10 cm long; cauline leaves spatulate or lanceolate to oblong-lanceolate, 5–15×2–7 cm, irregularly mucronulate-serrate, apex obtuse-acute; petiole winged almost to base, 3–5 cm long; apex acute, base cuneate to attenuate, short petiole or sessile; radical and lower cauline leaves usually withered and deciduous at anthesis.
• Heads several to many in terminal corymbs, 5–7 mm long, 10–15 mm across, pedunculate. Involucre hemispheric, bracts 3-seriate, outer bracts ca. 1.5 mm long, inner bracts ca. 3.5×0.5–1 mm, herbaceous, lanceolate, acute, margins scarious. Ray florets many, in 2 rows, tube 1–1.5 mm long; ligule white or tinged purple, linear, 3–5×0.3–0.5 mm, sparsely hirsute below ligule. Disc florets numerous, corolla tubular, narrowly funnelform, 2 mm long, upper part 4 times as long as lower part, 5-lobed, lobes triangular.
• Achenes oblong-oblanceolate, slightly compressed, 0.7–1 mm long, strigose, ribbed on both sides, pale umber. Pappus of disc florets brownish white, long and short bristles mixed in one row, longer ones to ca. 2 mm. Ray florets without pappus.
• Chromosome number, 2n = 27 (Peng & Hsu, 1978).

物候

Fl. Apr-Sep, sometimes Dec-Jan.

分布

• 台灣 : naturalized at low to mid elevations in the north.
• 世界 : Native of North America.

引證標本

TAIPEI: Shirmen, Peng 6349; Nankang, Peng 11596. TAOYUAN: Paling, Peng 11020. HSINCHU: Taoshan, Peng 8389; Kuanwu, Peng 9361. MIAOLI: Tunglo to Wumeikeng, Peng 11548. HUALIEN: Mukuashan, Peng 7351.

參考文獻

• PENG, Ching-I & CHUNG, Kuo-Fang; LI, Hui-Lin, Flora of Taiwan, second edition 4: 946. 1998.  (Fl. Taiwan 2nd edit.)