A thorny, deep-rooted tree of the valley edge and the desert wadis, chief among them the Nile thorn tree (Vachellia nilotica), which outlasts a drought that kills watered plants. Its hard, durable wood made boat timbers, dowels, tool handles and furniture, and Herodotus describes Nile cargo boats built of it; its seed pods tanned leather, and the gum of related trees bound pigments and medicines.