I found this here

This is the well-known fruit of the Common Bramble (Rubus fructicosus), which grows in every English hedgerow, and which belongs to the Rose order of plants. It has long been esteemed for its bark and leaves as a capital astringent, these containing much tannin; also for its fruit, which is supplied with malic and citric acids, pectin, and albumen. Blackberries go often by the name of “bumblekites,” from “bumble,” the cry of the bittern, and kyte, a Scotch word for belly; the name bumblekite being applied, says Dr. Prior, “from the rumbling and bumbling caused in the bellies of children who eat the fruit too greedily.” “Rubus” is from the Latin ruber, red.