Polygonum hydropiper

Species: Polygonum hydropiper

English Name: Water Smartweed

Chinese Name: 水蓼

Family: Polygonaceae

Herbs annual. Stems erect, 40-70 cm tall, much branched, glabrous, dilated at nodes. Leaves with peppery taste; petiole 4-8 mm; leaf blade lanceolate or elliptic-lanceolate, 4-8 × 0.5-25 cm, both surfaces glabrous, densely brown punctate, sometimes appressed hispidulous along midvein, base cuneate, margin ciliate, apex acuminate; cleistogamous flowers present in many leaf axils; ocrea tubular, 1-1.5 cm, membranous, sparsely appressed hispidulous, apex truncate, shortly ciliate. Inflorescence terminal or axillary, spicate, pendulous, interrupted below, usually lax, 3-8 cm, slender; bracts green, funnel-shaped, 2-3 mm, margin membranous, sparsely shortly ciliate, each 3-5-flowered. Pedicels longer than bracts. Perianth greenish, white or pink above, 5(or 4)-parted, brownish pellucid glandular punctate; tepals elliptic, 3-3.5 mm. Stamens 6, rarely 8, included. Styles 2 or 3. Achenes included in persistent perianth, black-brown, opaque, ovoid, biconvex or trigonous, 2-3 mm, densely small pitted. Fl. May-Sep, fr. Jun-Oct. 2n = 18-22.

Photos used under a Creative Commons license


– Wu ZY, Raven PH, Hong DY (eds) (2003). Flora of China, Volume 5: Ulmaceae through Basellaceae. Science Press, Beijing, and Missouri Bot Garden Press, St. Louis