生活型

herb

形態特徵

• Annual herbs, dwarf, erect to decumbent, densely white woolly-tomentose, especially in upper part; stems slender, simple or more commonly much branched, 8-25 cm tall, 0.5-1.5 mm across.
• Leaves grayish-green, spatulate or oblanceolate oblong, 1.5-4.5 cm long and 3-8 mm wide, obtuse and apiculate, narrowed to the sessile petioliform base, entire with wavy margins, the margins and the lower midribs sometimes flushed with purple, thinly appressed-tomentose on both surfaces.
• Heads campanulate, 2.5-3 mm high and 2-2.5 mm across, densely wooly to 2/3 from base, 2-5 in number, arranging in a spike to 2 cm long, at the tips of stems and branches; phallaries 3-seriate, loosely imbricated, graduated, elliptical ovate, elliptic to linear-oblong, acute, 1.6-2.2 mm long and 0.5-0.8 mm wide, scarious, with pale brown apex, red-purple middle and green base, these becoming brown when dry. Outer florets many, corolla filiform, 1.2 mm long, greenish yellow, the apex minutely 2-3 lobed, flushed with purple; central florets 5 or 6, tubular, greenish yellow, 1.5 mm long and 0.5 mm wide, 5-toothed at apex, the teeth flushed with purple; stamens yellow, 0.6 mm long; anthers sagittate at base, connate into a tube around the style; style white, 1.6 mm long, the style-branches linear, flushed with orange-yellow; ovary cylindrical, olivaceous, 0.5 mm long. Receptacle 1.3 mm across, pitted.
• Achenes oblong-rectangular, 0.5 mm long, pale brown, minutely punctuate. Pappus whitish, about 1.2 mm long, the bristles 5-8 in number, distinct, falling separately.
• This plant is often confused in herbarium specimens with <i>G. purpureum</i> L., however, the two are quite distinct from each other. Apart from the larger habit and the less branched stems, the latter has pappus bristles coherent at the base into a ring.

物候

The flowering season is restricted to the period between December and May.

分布

• 台灣 : as an annual weed in moist sunny places at roadsides, grasslands and also in and around cultivated fields.
• 世界 : tropical and subtropical Africa, Asia, China, Australia and tropical America.

引證標本

Hualien Co.: Hualien, along borders of paddy fields, 15 April 2000, Chen, s. n (NHU); Sing-cherng, along borders of paddy fields, 10 April 2001, Chen s. n. (NHU). Taitung Co.: Provincial Highway No. 11, 115.5K, along trail to mountain, 20 January 2003, Yang & Liu s. n. (NHU); Shan-wu, Hsu 13361 (TAI). Tainan Co.: Tung-shan, along borders of paddy fields, 5 April 2003. Ju s. n. (NHU); Go-i Bridge, along borders of paddy fields, 5 April 2003, Ju s. n. (NHU). Chiayi Co.: Minsiung, nearby roadside, along borders of paddy fields, 15 February 2004, Jeng s. n. (NHU); Nan-tan Water Work, in dried swampy bogs, close to a grave, Hsu & Kuo 6708 (TAI). Taichung Co.: Ching-shuei, weeds on ridges between plots of drained paddy field, Peng 4488 (HAST). Taichung: Pei-tun Dist., Shui-pien-tou, alt. 145 m, on unplowing rice field, Wang 4660 (HAST). Miaoli Co.: Yuan-li, on moist fallow paddy bank, expose, occasional, Peng et al. 17945 (HAST). Taoyuan Co.: Ping-jeng, along roadside, 15 February 2004, Feng s. n. (NHU); Yang-mei, along borders of paddy fields, 17 December 2005, Deng s. n. (NHU). Taipei: Mokusaku, 10 March 1929, Sasaki s. n. (TAI); Shui-uan-di, December 1934, Shimizu s. n (TAI). CHINA. GUANGDONG: Guangzhou City: suburbs, near Shi-pai, along paddy field, Hosokawa 10241 (TAI). HAINAN: Ler-an to Van-zon Gun, 17 March 1942, Yamamoto s. n. (TAI).

引用文獻

• Shih-Huei Chen and Ming-Jou Wu, Taiwania 51(3): 219. 2006.