生活型

herb

形態特徵

• Annual herbs. Stems erect or ascending, branched at base, rarely decumbent, forming circular patches, sparsely hirsute.
• Leaves alternate, scarcely pubescent on both surfaces, hairs slightly longer on veins, lower surface obscurely glandular punctate, obovate to spatulate, apex obtuse, base attenuate, sometimes auriculate, pinnately lobed or cleft, lateral segments 2–5 pairs, segments serrate, ciliate, 25–80 mm long, 15–30 mm wide, sessile or sometimes winged petiolate.
• Heads globose to spheroid, leaf-opposed, 5–10 mm long, 6–12 mm across, peduncle 5–28 mm long, terminating stems and branches. Involucre shallowly bowl shaped, bracts 2-seriate, subequal, obtuse to rounded at apex, margins irregularly dentate, ciliate on margins, densely hirsute, outer bracts oblong-lanceolate, 4–5.5 mm long, inner bracts obovate-oblanceolate, slightly shorter than outer. Receptacle convex. Ray florets many, in 5 or 6 rows, corolla white, narrowly tubular, ca. 1.5 mm long, 2–4 lobed, glandular dotted, style exserted. Disc florets many, corolla white, ca. 1.5 mm long, abundantly glandular dotted, lobes 5, triangular.
• Achenes pale brown, compressed, oblong, ca. 1.5 mm long, abundantly glandular punctate. Pappus persistent, crown shaped, 1 mm long, irregularly ciliate at tip, sparsely glandular dotted.
• Chromosome number, 2n = 18 (Peng & Hsu, 1978).

物候

Flowering from Nov to Jun.

分布

• 台灣 : a common weed in the south, growing in marshy waste places, rice fields and wet ground.
• 世界 : Africa, India, Indo-China and Java.

引證標本

NANTOU: Sun Moon Lake, Peng 10417. TAINAN: estuary of Tsengwen River, Wang 7963; Tungshan, Peng 8903. CHIAYI: Shuishang, Yen 4; Nantan Water Work, Hsu et Kuo 6707. KAOHSIUNG: Chishan, Huang 2419. PINGTUNG: Kenting, Peng 12513; Szuchunghsi, Peng 6814. TAITUNG: Shangwu, Hsu 13353A.

參考文獻

• PENG, Ching-I & CHUNG, Kuo-Fang; LI, Hui-Lin, Flora of Taiwan, second edition 4: 982. 1998.  (Fl. Taiwan 2nd edit.)