Warts are caused by the papilloma virus, of which there are 30 types.
Warts infect only the topmost layer of the skin.
They do not have roots, seeds, or branches, but do have capillaries that give some warts a black dot appearance. This is a result of the rapid skin growth caused by the wart virus. Firm, sharply defined, round or irregular. These growths range in color from flesh-colored to brown and measure up to 6mm in diameter. They may itch.