Lithops are self-sterile, so that seed will only be produced if the plant is pollinated from another specimen from a different clone or group. Yellow flowers will not fertilize white and vice-versa. There is not the same range of flower colour as shown by the conophytums; lithops’ flowers are either white or yellow.
Source: wiktionary
And the succulents house, which is kept a cool 60 degrees during the day and 50 to 55 degrees at night, holds aloes and lithops (which look like small stones), just beginning to bloom.
Source: wiktionary
Lithops (‘Lithops’ singular) are easily one of Earth's weirdest plants making them highly popular with succulent lovers. They're also infamous for being easy to kill. In fact, I bet we'd be hard pressed to find someone who has never killed a Lithops unless they've just never had one, and that doesn't count.
Source: wiktionary