11. Polygonum patulum M. Bieb., Fl. Taur.-Cauc. 1: 304. 1808; Kom., Fl. URSS 5: 630. 1936; Webb & Chater in Tutin et al, Fl. Europ. 1: 78. 1964; Rech. f. & Schiman-Czeika in Rech. f., Fl. Iran. 56: 80. 1968; R.R.Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 211. 1972; Bhopal & Chaudhri in Pak. Syst. 1(2): 82. 1977. (Fig.14, F-J).
P. bellardii auct. non All, Fl. Pedem. 2: 207. t. 90. fig. 2. 1785: Boiss., Fl. Or. 4: 1034. 1879; P. bellardii var. patulum (M. Bieb.) Meisn. in DC.; Prodr. 14: 999. 1856; P. kitaibelianum Sadl., Fl. Pest. 1: 287. 1825.
Erect, 25-80 cm tall, glabrous, annual herb, usually much branched from the base. Branches, ± spreading, thin and striated; internodes 2-2.4 cm long. Leaves few, 10-50 x 3-8 mm, linear-lanceolate to oblong-elliptic, acute, entire, subsessile, often caducous. Ochrea hyaline, 3-7 (-9) mm long, ovate, fringed-lacerate, distinctly nerved, flowering branches leafy only in the lower part. Flowers solitary or in axillary clusters of 1-4, 2.0-3 mm across, pedicellate, pedicel 1-2 mm long. Ochreolae 1.5-2.5 mm long, ovate, lacerate to fringed, tubular, membranous at the margin, green in the middle. Tepals 5, greenish to pinkish, 1.5-3.0 x 1.0-1.5 mm, lobed almost up to the base, lanceolate, acute, entire, unqual. Stamens 5(-7), filaments short, equal, ovary 0.75-1.25 (-1.5) x 0.5-1.0 mm, ovate, trigonous, styles 3, stigmas capitate. Nuts 2-3 x 1.0-2 mm, triquetrous, dark brown, shining, glabrous.
Fl. Per.: March-June.
Type: Tauria, M. Bieberstein (LE).
A widespread species, occurring from plains to 2500 m, among rock crevices and stones; Distribution: Europe, S. W. Asia and N. Africa.
Plants with larger nuts are often referred to under a separate species Polygonum kitaibelianum Sadl. However, the variation in nut size seems to be ± continuous and it is very difficult to draw a line using this character.