polygonaceous

a. [ See Polygonum. ] (Bot.) Of or pertaining to a natural order of apetalous plants (Polygonaceæ), of which the knotweeds (species of Polygonum) are the type, and which includes also the docks (Rumex), the buckwheat, rhubarb, sea grape (Coccoloba), and several other genera. [ 1913 Webster ]