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Flora of Taiwan | Family List | Compositae | Conyza

Conyza sumatrensis (Retz.) Walker, J. Jap. Bot. 46: 72. 1971; Chen, Fl. Reipubl. Popul. Sin. 74: 350, pl. 88: figs. 1-4. 1985.


  • Erigeron sumatrensis Retz.

    Annual herbs. Stems erect, grayish green, 50-150 cm tall, branching upward or sometimes not, hirsute pubescent. Basal and lower leaves withered but persistent at anthesis, lower and middle cauline leaves oblanceolate to lanceolate, 4-10 cm long, 0.5-1.5 cm wide, apex acute, base attenuate, margins generally few toothed apically or subentire; upper leaves smaller, linear to lanceolate, subentire, pubescent on both surfaces. Heads numerous, in large panicles, 3-5 mm long, 5-8 mm across, pedunculate. Involucre urceolate, bracts 3-seriate, linear lanceolate, acute, sparsely hirsute, outer ones shorter, 2-3 mm long, inner ones ca. 5 mm long, margins scarious. Ray florets many, in 3 or 4 rows, filiform-tubular, ligules minute, obscure, 3-4 mm long, nearly equalling pappus, yellowish. Disc florets 5-10, corolla narrowly tubular, ca. 5 mm long, gradually opening upward, 5-lobed, yellowish. Achenes oblong-oblanceolate, 0.7-1.5 mm long, 0.3-0.4 mm wide, compressed, ribbed on both sides, minutely pubescent, pale umber. Pappus tawny, capillary, bristles 1-seriate, 5 mm long at maturity, persistent. Flowering year round in Taiwan. Chromosome number, 2n = 54 (Peng & Hsu, 1978).

    TAIPEI: Taipei City, Peng 6045. TAOYUAN: Yungan Port, Peng 12769; Hsiayun-Hsiayunping, Peng 10279. MIAOLI: Yuanli, Peng 11111. TAICHUNG: Wuling, Peng 11059. NANTOU: Chingjing Farm, Peng 6090; Lulin Lodge to Tatachia Saddle, Peng 11444. HUALIEN: Kuanyuan, Peng 9194; Tayuling, Peng 13135.

    A pantropical weed of South American origin, early established in Sumatra. Taiwan, very common in open, waste fields and construction sites from lowlands to 2,000 m.


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