a. the tropical, half-hardy, climbing trees and shrubs;
b. the shrubby buckwheats of arid habitats in south-eastern Europe, central Asia, and N. America; and
c. the temperate species, including the edible species (e.g. Rheum rhaponticum, rhubarb, and Fagopyrym esculentum, common buckwheat), the ornamentals (e.g. Muehlenbeckia species and Erigonum species), and the weeds (e.g. Rumex species, sorrels and docks). There are 51 genera, comprising about 1050 species, distributed throughout the world, but with a concentration in the northern temperate regions.
"Polygonaceae." A Dictionary of Plant Sciences. . Encyclopedia.com. (October 15, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/polygonaceae
"Polygonaceae." A Dictionary of Plant Sciences. . Retrieved October 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/polygonaceae