An architectural stunner for those with a casual (forgetful) approach to watering. These fleshy lances are well-adapted to tolerate seasonally dry and arid conditions. Appropriately alien-looking, they have actually been into space, forming part of NASA's study into air purification on their space stations. They'll be equally happy here on Earth, too, orbiting the sun contentedly on a bright windowsill. Surprisingly cold-resistant (but never frost!) as long as the roots are dry.