David in Normandy wrote:
Martin Brown wrote:

But they are fairly promiscuous and a lot of the ones sold these days
are hybrids of Schlumbergia (Zygocactus) truncatus. You can get a wide
range of colours although yellow and white are rarer and will not come
true if the house is too cold - the pink will still be expressed.

Ah!!! We had one with pink flowers in Winter, but strangely had white
flowers this Summer - this confused both me and the Mrs. I thought
perhaps she had swapped it for another one on the windowsill. So they
CAN change flower colour then?

They are nominally white or yellow. But if you don't keep them warm
enough while the flowers are in formation the dominant pink pigment
still gets expressed. My house isn't quite warm enough most winters so
my "pure" white ones usually have at least tinge of pink.

I am still on the lookout for a decent yellow one.

Regards,
Martin Brown