10. Polygonum argyrocoleum Steud. ex Kunze in Linnaea. 20: 17. 1847; Boiss., Fl. Or. 4: 1035, 1879; Steward in Gray Herb. Harvard Univ. 19. 1930; Kom., Fl. URSS 5: 636. t. xxxxiv. f. 1. 1936; Kitamura, Fl. Afghan. 89. 1960; Rech. f. & Schiman-Czeika in Rech. f., Fl. Iran. 56: 82. 1968. R.R. Stewart, l.c. 203; Chaudhary, Fl. Kingd. Saudi Arab. 1: 305. 1999. (Fig.14, A-E).
Erect or ascending, 30-50 (-70) cm tall, glabrous herb, usually branched from the base or above, branches slender. Leaves few, linear or lanceolate, often deciduous, upper ones smaller, lower 15-30 (-40) x 2-4 (-8) mm, entire, glaucous, sessile to petiolate, petiole up to 5 mm long. Ochreae subhyaline to membranous, 5-12.5 mm long, lacerate, dark brown at the base, silvery above. Inflorescence solitary, axillary, flowering branches ± naked, with long internodes. Flowers white to pinkish white, 1-2 mm across, pedicel slightly exserted from the ochreolae, 1.5-2 mm long; ochreolae 1-2 mm long, membranous, bifid. Tepals 5, parted about half the length, 1.5-2.0 x c. 1.0 mm, oblanceolate, entire, 3-veined. Stamens 6, filaments short, equal with broad base, alternating with the glands. Styles 3, short, fused about half the length or more, stigma capitate. Nuts 1.5-2 x 1-1.5 mm, trigonous, brown, smooth, shining, included within the perianth.
Fl. Per.: June-September.
Type: In arena insularum Tigridis prope Mossul, 2nd Sept. 1841, Kotschy (specimena fructifera).
An Irano-Turanian element, occurring between 1500-2500 m near water channels and also grows as a weed. Often confused with P. patulum M. Bieb. due to similar habit and almost leafless floral branches which are conspicuously different from the leafy vegetative branches in both the taxa. However, in P. argyrocoleum the inflorescence is compact and the nuts are small. Whereas in P. patulum the inflorescence is lax, interrupted and the nuts are large; Distribution: Iraq, Iran, Pakistan, Afghanistan, Central Asia including Turkmenistan, Georgia (Caucasia).