14. Polygonum olivascens Rech. f. & Schiman-Czeika in Rech. f., Fl. Iran. 58: 80. 1968; R.R.Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 207. 1972.
Prostrate-suberect, branched, glabrous, annual herb. Stem branched from the base, branches divaricate, 10-20 mm long, lineolate, fragile or woody. Leaves cauline and on secondary branches, olive-dirty green, cauline leaves 1.5-2.25 x 0.4-0.5 mm, elliptic-linear or lanceolate, ramal leaves much smaller, 0.8-1.0 x 1-2 mm, linear-lanceolate, acute-obtuse, sessile. Ochreae 4-6 mm long, membranous, tubular to infundibuliform, bifid, fimbriate-lacinate. Inflorescence fasciculate, solitary. Flowers 1.0-2.5 mm across, shortly pedicellate, pedicel 2.5-3 mm long. Ochreolae small, tubular. Tepals 5, 2-2.5 (-3) x 0.75-1.0 mm, oblanceolate. Stamens 6-8, filaments long, filiform. Ovary 2-3 x 1.5-2.0 mm, ovate-circular, trigonous with three short styles and capitate stigmas. Nuts 2.5-3.0 x 2.0-2.5 mm, trigonous, brownish, shining.
Fl. Per.: April-July.
Type: Iran: Kerman - Inter Saidabad et Jugum Chah-e-Chaghak, 1700-1900, 28.4.1948, Rechinger 3159 (W).
Distribution: Iran, Afghanistan and Pakistan.
This Irano-Turanian element is closely related to Polygonum aviculare in habit and having heterophyllous leaves, but the nuts are different in both the species. In P. aviculare the nuts are rugulose and dark brown whereas in P. olivascens the nuts are smooth, yellowish-light brown and shining. In P. aviculare the branches are striate whereas in the latter species the branches are not striate.