Any of a group of red pigments found mainly in plants of the order Chenopodiales, which includes the goosefoot, cactus, and portulaca families. They are nitrogen-containing glycosylated compounds responsible for the red colour of beetroot, for example, and are chemically distinct from the anthocyanins, which include many red and pink plant pigments. A group of yellow pigments, called betaxanthins, are chemically similar to betacyanins and are restricted to the same families. Both betacyanins and betaxanthins are classed as betalains.