《中国植物志》|| 蓼科 POLYGONACEAE ||萹蓄组 Sect. Avicularia Meisn. ||萹蓄 Polygonum aviculare L.

6.萹蓄（神农本草经，植物名实图考）扁竹，竹叶草
Polygonum aviculare L. Sp. Pl. 362. 1753; Hook. f. Brit. Ind. 5: 26. 1886; Forb. et Hemsl. in Journ. Linn. Soc. Bot. 26: 334. 1891; Sam. in Hand.-Mazz. Symb. Sin. 7: 172. 1929; Stew. in Contr. Gray Herb. 88: 20. 1930; Kung in Ill. N. Chine 5: 33. pl. 12. 1936: 东北草本植物志2: 31. 图23. 1959;湖北植物志1: 222.图294. 1976; Kitag. Neo-Lineam. Fl. Mansh. 242. 1979: 西藏植物志1: 609. 1983; Borod. in Pl. Asiae Centr. 9: 101. 1989.——P. Monspeliense Thieb. ex Pers. Syn. Pl. 1: 439. 1805. ——P. heterophyllum Lindm. Svensk Bot. Tidskr. 6 (3): 1912.——P. aviculare L. var. vegetum Ledeb. Fl. Ross. 3: 532. 1849.
一年生草本。茎平卧、上升或直立，高10-40厘米，自基部多分枝，具纵棱。叶椭圆形，狭椭圆形或披针形，长1-4厘米，宽3-12毫米，顶端钝圆或急尖，基部楔形，边缘全缘，两面无毛，下面侧脉明显；叶柄短或近无柄，基部具关节；托叶鞘膜质，下部褐色，上部白色，撕裂脉明显。花单生或数朵簇生于叶腋，遍布于植株；苞片薄膜质；花梗细，顶部具关节；花被5深裂，花被片椭圆形，长2-2.5毫米，绿色，边缘白色或淡红色；雄蕊8,花丝基部扩展；花柱3,柱头头状。瘦果卵形，具3棱，长2.5-3毫米，黑褐色，密被由小点组成的细条纹，无光泽，与宿存花被近等长或稍超过。花期5-7月，果期6-8月。
产全国各地。生田边路、沟边湿地，海拔10-4200米。北温带广泛分布。
全草供药用，有通经利尿、清热解毒功效。

《Flora of China》|| Polygonaceae || Polygonum ||萹蓄 Polygonum aviculare

6. Polygonum aviculare Linnaeus, Sp. Pl. 1: 362. 1753.

萹蓄 bian xu

Herbs annual. Stems prostrate, ascending, or erect, 10-40 cm tall, much branched from base. Petiole short or nearly absent, articulate at base; leaf blade lanceolate or narrowly elliptic, 1-4 cm × 3-12 mm, both surfaces glabrous, midvein and lateral veins conspicuous, base cuneate, margin entire, apex acute or nearly obtuse; ocrea: lower part brown, upper part white or throughout brown, membranous, veined, apex lacerate. Flowers 1-5; axillary; bracts thinly membranous. Pedicel slender, articulate at apex. Perianth green, margin white or pinkish, 5-cleft to 2/3-3/4; tepals elliptic, 2-2.5 mm. Stamens 8; filaments dilated at base. Styles 3, free, short; stigmas capitate. Achenes included or slightly exceeding persistent perianth, black-brown, opaque, ovoid, trigonous, 2.5-3 mm, minutely granular striate. Fl. May-Jul, fr. Jul-Aug. 2n = 40, 60.

Near fields, roadsides, waste places; sea level to 4200 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [widely distributed in N temperate zone; widely naturalized in S temperate zone].

《Flora of North America》|| Polygonaceae || Polygonum || Polygonum aviculare

11. Polygonum aviculare Linnaeus, Sp. Pl. 1: 362. 1753.

Doorweed, knotgrass, renouée des oiseaux

Plants green or bluish green, green after drying, sometimes whitish from powdery mildew, homophyl-lous or heterophyllous. Stems prostrate to erect, branched, flex-uous, 5-200 cm. Leaves: ocrea 3-15 mm, proximal part cylindric or ± funnelform, distal part silvery, hyaline, soon disintegrating into persistent fibers or nearly completely deciduous; petiole 0.3-9 mm; blade green to gray-green, narrowly elliptic, lanceolate, elliptic, obovate, or spatulate, 6-50(-60) × 0.5-22 mm, margins flat, apex acute, obtuse, or rounded; stem leaves 1-4 times as long as adjacent branch leaves; distal leaves overtopping flowers. Inflorescences axillary; cymes uniformly distributed or aggregated at tips of stems and branches, 1-6(-8)-flowered. Pedicels enclosed in or exserted from ocreae, 1.5-5 mm. Flowers closed or semi-open; perianth 1.8-5.5 mm; tube 20-57% of perianth length; tepals overlapping or not, green or reddish brown with white, pink, or red margins, petaloid, not keeled, oblong to obovate, often cucullate in fruit; midveins branched or unbranched, thickened or not; stamens 5-8. Achenes enclosed in or exserted from perianth, light to dark brown, ovate, (2-)3-gonous, 1.2-4.2 mm, faces subequal or unequal, apex not beaked, edges slightly concave, dull, usually coarsely striate-tubercled, sometimes obscurely tubercled; late-season achenes common or not, 2-5 mm.

Subspecies 7+ (6 in the flora): nearly worldwide.

Polygonum aviculare is a taxonomically controversial polyploid complex of selfing annuals. Although members of the complex have been considered inbreeders, they possess some structures that make cross pollination possible. Cleistogamous and chasmogamous flowers, heterostyly, protandry, and the capacity to secrete nectar suggest an ancestral mixed-mating system. Isoenzyme studies showed that the complex has an allopolyploid origin (P. Meerts et al. 1998) and has evolved as a swarm of inbreeding lines (“Jordanons”) (J. Gasquez et al. 1978). The six subspecies included here have been treated variously (T. Karlsson 2000; M. Costea and F. J. Tardif 2003). Complex intergradation patterns among them make their recognition at the species level impractical. Multivariate analysis and isoenzyme studies show that populations with intermediate characteristics may occur (Meerts et al. 1990, 1998). Except for subsp. boreale, which occurs in Greenland and Labrador, all subspecies are partially sympatric and their distributions have been influenced greatly by humans.

SELECTED REFERENCES

Meerts, P., T. Baya, and C. Lefèbvre. 1998. Allozyme variation in the annual weed species complex Polygonum aviculare (Polygonaceae) in relation to ploidy level and colonizing ability. Pl. Syst. Evol. 211: 239-256. Meerts, P., J.-P. Briane, and C. Lefèbvre. 1990. A numerical taxonomic study of the Polygonum aviculare complex (Polygonaceae) in Belgium. Pl. Syst. Evol. 173: 71-90. Styles, B. T.  1962. The taxonomy of Polygonum aviculare and its allies in Britain. Watsonia 5: 177-214.