Family: Polygonaceae Synonyms: Fagopyrum cymosum, Fagopyrum emarginatum, Polygonum chinense, Polygonum dibotrys. Common Name: Perennial Buckwheat Local Name: Kathu (काठू). Kathu is an easily grown annual to perennial herb of Western Himalaya commonly found growing along roadside, pathways, moist shady slopes, ditches, fertile soils and in forests up to an altitude