Description from Flora of China
Persicaria sagittifolia H. Gross; P. senticosa (Meisner) H. Gross ex Nakai var. sagittifolia Yonekura & H. Ohashi; Polygonum sagittifolium H. Léveillé & Vaniot (1902), not Kuntze (1891); P. senticosum (Meisner) Franchet & Savatier var. sagittifolium C. W. Park; Truellum darrisii (H. Léveillé) Soják.
Herbs annual. Stems climbing or scandent, reddish purple, 1-2 cm tall, angulate, with sparse recurved prickles along angles. Petiole 3-6 cm, retrorsely prickly; leaf blade narrowly triangular or triangular-sagittate, 4-10 × 3-5 cm, abaxially sparsely prickly along midvein, adaxially glabrous, base sagittate, margin retrorsely prickly, apex acuminate; ocrea tubular, apex with green herbaceous lanceolate-auriculate wing, margin not ciliate. Inflorescence terminal or axillary, capitate; peduncle usually simple, sparsely prickly; bracts narrowly ovate, apex acuminate, usually each 2-flowered. Pedicels shorter than bracts. Perianth white or pinkish, 5-parted; tepals elliptic. Stamens 8, in 2 whorls, included. Styles 3, connate to middle; stigmas capitate. Achenes included in persistent perianth, black-brown, dull, subglobose, weakly trigonous, ca. 3 mm. Fl. Jun-Aug, fr. Sep-Oct.
One of us (Park) believes that this taxon should be recognized as a variety of Polygonum senticosum.
* Wet valleys, along ditches; 300-1700 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, Yunnan, Zhejiang.