45. Cirsium arvense (Linnaeus) Scopoli, Fl. Carniol., ed. 2. 2: 126. 1772.
丝路蓟 si lu ji
Herbs 30-160 cm tall, perennial, dioecious. Roots far creeping, bearing adventitious shoots. Stems erect, branched above, unwinged. Leaf surface smooth. Capitula often numerous, terminal, corymbose. Involucre ± narrowly ovoid, 1.5-2 cm in diam. Phyllaries imbricate, in 5-7 rows, lacking wings and scarious appendage; outer and middle phyllaries triangular to ovate, 3-8 × 1.2-2.5 mm, apex acute; inner phyllaries elliptic-lanceolate to broadly linear, 9-20 × 1-3 mm, apex acute to acuminate and scarious. Corolla reddish purple or rarely white; female florets 1.6-2.4 cm, tube 1.3-1.8 cm; male florets 1.5-1.8 cm, tube 0.9-1.2 cm. Achene yellowish, 3-4.5 mm. Pappus bristles dirty white, 2.5-3.5 cm.
Moist places, ditches, farmlands, lakesides, grasslands, mountain slopes, roadsides, near villages, by rivers, wet or flooded lands; 100-4300 m. Anhui, Chongqing, Fujian, Gansu, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Xizang, Zhejiang [Afghanistan, India, Japan, Kazakhstan, Korea, Mongolia, Nepal, Russia; SW Asia, Europe].
Cirsium arvense is one of the world’s most noxious weeds of cultivated land. Its strong potential for vegetative multiplication from long trailing roots or root fragments results in morphologically uniform clonal stands, which at times have led to the recognition of some of the variants as distinct species.