This cosmopolitan annual weed is an allotetraploid (2n = 44) that probably orginated in part from lapathifolia (Kim et al. 2008). The epithet maculata has been widely applied to the species (K), but apparently in error (FNA 5). Its leaf blades often have a dark triangular or lunate blotch on the upper surface. Such marks sometimes occur in lapathifolia, pennsylvanica and bicornis, but less clearly in longiseta. There is some traditional use of maculosa as a vegetable in Europe, and "persicarin" (a complex sulphated flavonoid) has much medicinal potential (Barron et al. 1988; and subsequent literature).