In most lithops species, occasionally 2 or more heads develop from the same rootstock, thereby becoming multi-headed by a process termed vegetative reproduction.
Single head developing into two
Often the leaves of the previous generation are retained in cultivation, but this is not a form of head multiplication. (See this phenomenon in Growth Cycle.)

The relationship between flowering and head multiplication has been investigated and of all taxa investigated,63% increased heads after flowering and 37% increased heads without flowering. It has also been suggested that increased nutrients lead to size increase only, not an increase in number of heads.