生活型

herb

形態特徵

• Annual glabrous herbs, aquatic or semi-aquatic, upright, 10-50 cm tall. Roots fibrous.
• Leaves dimorphic, glabrous on both surfaces. Radical leaves simple, 3-parited or more irregular lobed, 1.3-5.1 cm long, 2-8.2 cm wide; orbicular, ovate or deltoid, 3 or more lobed; apex acute; base rounded, truncate or cordate; margin coarsely irregular serrate; petioles 3-9.5 cm long. Cauline leaves 3-lobed to 3-parted, 2.2-4.2 cm long, 3.3-6 cm wide; segments narrowly elliptic or narrowly oblong; apex acute; base rounded or turncate; margin coarsely and irregularly serrate or entire; short petiolate or subsessile.
• Inflorescence a terminal cyme; pedicels 5-27 mm long, sparsely pubescent. Flowers 5-8 mm long in diam., yellow; sepals 5, 2.5-3.5 mm long, spreading, broadly elliptic or elliptic, pubescent outside, glabrous inside; petals 5, 3-4 mm long, obovate, glabrous on both sides; stamens more than 10, 1.5-2 mm long, anthers ovate or oblong, ca. 0.5 mm long, filaments linear; carpels many, glabrous; receptacle glabrous.
• Fruiting head ellipsoid; achenes ca. 1 mm long, obovoid-orbicular, glabrous, laterally compressed; styles persistent, short.

物候

Flowering January to May; fruiting Feburary to June or to summer.

分布

• 台灣 : open places, stream sides and forest margins throughout.
• 世界 : Widely distributed in temperate and subtropical areas worldwide.

引證標本

TAIPEI: Auoti, Huang 3517; Yuanshan, Chou et al. 7575. HSINCHU: Lake Chintsaohu, Huang & Huang 13024. TAICHUNG: Kanglangli, Peng 4480. TAITUNG: S. Cross-Island Highway, Hsianyang, Kuoh 11276.

參考文獻

• YANG, T. Y. ALECK and HUANG, TSENG-CHIENG. 1996. Flora of Taiwan, second edition 2: 560. (Fl. Taiwan 2nd edit.)