The seeds of all the taxa of the genus Lithops N.E.Br. are hereby described following their study by both digital dissection microscope and scanning electron microscopy. This information is used together with all other taxonomically important data to suggest the best possible classification for the genus. As a consequence of this new information, L. bella, L. dendritica and L. eberlanzii are reinstated as full species whilst four varieties are elevated to subspecies status. The varieties of L. karasmontana are no longer recognised except for var. aiaisensis which is transferred to L. eberlanzii due to its identical seeds. L. dendritica now comprises of four subspecies, all of which have seeds vastly different from L. pseudotruncatella, under which they were formerly classified.