Cactus for ID : Flower Show,Mumbai : 020313 : AK-3: Another cactus seen at the Flower Show in Mumbai in Feb,2011.
Cultivated, potted plant.
There are a few that look like this …, And not sure why it is grafted, as they are all easy on their own roots. I have one that is named M. craigii (syn – sonorensis ‘craigii’) that is similar and same flowers, montensis is another, petterssonii another similar and zuccariniana. But I think there are more and they can vary. Personally, I think that one is probably craigii, but really cannot be sure.