Polygonum senticosum

Polygonum senticosum

　　Polygonum senticosum

　　It is a perennial herb with a thick, hook-shaped, black rhizome densely covered with remnants of old stems, leaves, and ocreae. The stem grows 10–40 cm tall, has (4)5–6 nodes, and is glabrous. The ocreae are membranous, rusty-colored, cylindrical, slightly wider at the upper part, with oblique tips. Those on the upper stem are brownish-green with dry, membranous, rusty-colored upper ends, sometimes pubescent; the leaves are leathery, densely pubescent on the underside, entire or slightly undulate. The basal leaves have relatively long petioles, about 7 cm long, with blades that are narrowly ovate-lanceolate or ovate-oblong, (3)4–7 cm long and 1–3 cm wide, with a rounded or slightly cordate base that is not decurrent or only slightly so, and tapering to a point. The lower and middle stem leaves have shorter or no petioles, while the upper leaves are triangular-lanceolate with cordate bases, sessile, and clasping the stem. The uppermost leaves are very small, linear or bristly, and sometimes absent. The inflorescence is pink, cylindrical, stout and short, about 2–3 cm long or slightly longer, with a diameter of 1.4–1.6 cm, and densely flowered; the bracts are dry, membranous, rusty-colored, broadly ovate or elliptic, about 4 cm long and 3 cm wide, with long tail-like tips; the perianth is deeply 5-lobed, with lobes oblong or oval, about 3 mm long, 1.2–1.5 mm wide; there are 8 stamens with filiform filaments and purplish anthers, and 3 slender styles. The small, compact fruit is trigonous, shortly pointed at the tip, brown, and glossy.

　　It grows in alpine tundra and is distributed in the Russian Far East and China (Northeast).