29. Erigeron annuus (Linnaeus) Persoon, Syn. Pl. 2: 431. 1807.
一年蓬 yi nian peng
Aster annuus Linnaeus, Sp. Pl. 2: 875. 1753; Erigeron heterophyllus Muhlenberg ex Willdenow; Stenactis annua (Linnaeus) Cassini ex Lessing.
Herbs, annual, [10-]30-100[-150] cm tall. Stems erect, branched in upper part, sparsely hispid, strigose above (hairs spreading). Leaves: surfaces strigose-hirsute or sometimes glabrate, eglandular; basal withered at anthesis, winged petiolate, blade elliptic or broadly ovate, rarely spatulate, 4-17 × 1.5-4 cm or more, base attenuate, margin coarsely serrate, scabrous, apex acute or obtuse; lower cauline similar, shortly petiolate, mid and upper shortly petiolate or sessile, blade oblong-lanceolate or lanceolate, 1-9 × [0.3-]0.5-2 cm, margin irregularly serrate to subentire, apex acute, uppermost linear. Capitula 5-50+, in loose paniculiform or corymbiform synflorescences, 6-8 × 10-15 mm. Involucre hemispheric; phyllaries 2- or 3(or 4)-seriate, greenish or ± brownish, abaxially sparsely hirsute, minutely glandular, subequal or outer shorter, lanceolate, 3-5 × 0.5-1 mm, herbaceous. Ray florets 80-125, 2-seriate, [4-]6-8[-10] mm, tube 1-1.5 mm, sparsely hairy above, lamina white or sometimes bluish, linear, ca. 5 × 0.6 mm, flat, tardily coiling; disk florets yellow, 2-2.8 mm, sparsely hairy, lobes glabrous. Achenes lanceolate, flattened, [0.8-]1.2 mm, sparsely strigillose. Pappus 2-seriate, outer of scales or setae, inner absent in ray florets, in disk florets of [8-]10-15 long bristles. Fl. Jun-Sep.
Wastelands, roadsides; sea level to 1100 m. Naturalized in Anhui, Fujian, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Shandong, Sichuan, Xizang [native to E North America; widely introduced worldwide].
This species is spreading in China and is probably more widespread than shown here.