Lappa IV was a planet inhabited by the Ferengi. Zan Periculi, a species of flower, was native to this world. (TNG: "Ménage à Troi")
According to the Star Trek: Star Charts ("United Federation of Planets I"), the Lappa system was located in or near Ferengi space, in the Alpha Quadrant. The system was a single star system. Primary was a Class K star with a magnitude of +7, which was 1/10 as bright as Sol.