Mammillaria elongata cristata, known as the "Brain Cactus", forms attractive undulating fan-like stems covered in dense golden spines. Cristate forms generally occur when injury occurs to the plant at a young age (this damage can be due to insects eating the growing tip, or from many other causes, including a genetic predisposition). In reaction to the "injury", the cells at the tip of the branch where growth occurs begin to multiply at a much faster rate and the normal growing tip "goes crazy", creating fantastic whorls and fans. Mammillaria elongata, in habitat, lives in crags between rocky outcroppings in Central Mexico, eventually forming long cascades of stems with pendant offsets. In this habitat, the water drains quickly away from the roots of the plant, never allowing the plant to remain waterlogged. For this reason, it is essential in cultivation to use a very porous soil, which will allow quick drainage. Bright, filtered light. Water thoroughly when soil is dry to the touch. As the "fans" of cristates can trap water that can lead to rot, it is preferable to water from beneath, if possible. Water thoroughly when soil is dry to the touch, except on cloudy, humid or cold winter days. Protect from frost. Shipped established in a 3.5" pot.