Polygonum L., Sp. Pl. 1: 359. 1753; Gen. Pl. 2: 116. 1754; Hook. f., Fl. Brit. India 5: 23. 1890; Webb & Chater in Tutin et al., Fl. Europ. 1: 76. 1964; Collett, Fl. Siml. ed. 2: 419. 1921 (Reprint 1980); Fl. North Amer. @ eFloras.org vol. 5; Fl. Pak. @ eFloras.org Pakistan V. 205.

Herbs, rarely subshrubs; annual or perennial. Stem erect, prostrate or subprostrate or ascending, branched, with conspicuously swollen nodes, glabrous or pubescent. Leaves cauline, alternate, subsessile, small, linear-lanceolate, ovate, elliptic or subrotund, margin entire. Ochrea small, silvery or whitish hyaline, membranous, partite or ciliate-lacerate at apex. Inflorescence axillary, few-flowered or solitary or in small clusters. Pedicels often articulate. Flowers bisexual, rarely unisexual, 1-7(-10) per ochreate fascicle. Perianth persistent, non-accrescent, mostly petaloid, white, greenish white or pink, campanulate to urceolate, glabrous; tepals (4-)5(-6), connate up to 2/3rd of their length, mostly monomorphic, elliptic-ovate. Stamens 4-8; filaments short, usually broadened at base without any interstaminal nectaries, free or adnate to perianth tube, glabrous. Ovary biconvex or trigonous, small; styles 2(-3), mostly elongate and spreading, free or connate proximally; stigmas capitate. Achenes biconvex or trigonous, rarely biconcave, not winged, dark brown- black, shiny, glabrous.

163 species

Polygonum effusum Meisn., Prodr. 14: 93. 1856; 1921 (Reprint 1980); Fl. Pak. @ eFloras.org Pakistan V. 205; P. plebeium R. Br. var. effusum (Meisn.) Hook. f., Fl. Brit. India 5: 28. 1890.

Prostrate, annual herb, forming mats. Stem green or reddish-brown, up to 50 cm long, profusely branched, glabrous, channelled, internodes long. Leaves all similar, subsessile, narrowly linear, oblong or spathulate, attenuate to base, dark green to reddish- brown, up to 28 mm x 3 mm, acute or obtuse and slightly mucronate at apex, margin revolute, midvein inconspicuous adaxially and conspicuous abaxially. Ochrea tubular, membranous, lacerate at mouth, with inconspicuous veins, glabrous. Inflorescence an axillary cluster of 1-3(-5) flowers per cluster. Flowers actinomorphic, bisexual, hypogynous, pedicellate, clearly exserted from ochrea; pedicels 1.75-2.5 mm long, articulated, articulation almost in the middle of pedicel or slightly above. Tepals 5, pink, eventually turning white, all+/- equal, ca. 1.7 mm long, obovate with rounded apex. Stamens 8, filaments short, ca. 0.8 mm long, usually broadened at base. Carpels 3, syncarpous; ovary ca. 1 mm long, trigonous, unilocular with 1 ovule; styles 3 with capitate stigma. Achenes ( nuts) trigonous, black and shining.

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