Abstract: Fagopyrum densovillosum J. L. Liu, a new species of the polygonaceae from Luojishanzhen, Puge Country, Sichuan Province, China，is described. F. densovillosum is closely related to F. gracilipes (Hemsl.) Damm. et Diels By its from bottom to top foliate stems and branches, axillary and apical Racemes, ovate-triangular or broadly ovate-triangular achenes, but differs in its densely erect-villose plants, thicker stems and branches, densely nodes, shorter internodes, broadly ovate, cordate, broadly cordate, broadly ovate-cordate, ovate, long ovate, triangular-ovate or ovate-triangular and larger leaves,（0.9-）1.7-6 cm long and （0.7-）1.2-5.1 cm wide, thin rugose and small pustulate on the surface, longer petioles (0.5-)2.6-7.5 cm long, smaller achenes 1.8-2.5 mm long and 1.5-2 mm in diameter.

Key words: Fagopyrum, Fagopyrum densovillosum J. L. Liu, Polygonaceae, new species, Sichuan, China