Hola Bromelia,

I think you might mean 'Fairy Castle'....I believe the one on the left is known by that cultivar name. There's also a crested version, too, IIRC, while your one on the left is monstrose.

Salud,

El Jeffe de Tequila Desayuno

Aren't Fairy Castles a form of Euphorbia?

aka Acanthocereus tetragonus 'Fairy Castle'. I had several of these... really cool little cacti.

Geoff is correct, Bromelia, for the specialized name of the genus. Karen, that could be, but it'd be a first for me (not a Euexpert).