This genus consists of a single species - the Monvillea spegazzinii - which for some classifications could be considered a part of the Cereus family. This plant has characteristics, that allow it to be easily distinguished from the others: it consists of long thin and ribbed stems, of a typical dark color, which tend to cluster and form a particular and unique tangle. Commonly known by the name of the "plant in the moonlight", it has in fact the particular characteristic of having large white and very fragrant nocturnal blooms. But the real peculiarity for which it is appreciated, is its crested shape: together with the normal stems, its bluish crests form an effect similar to a marble sculpture. It is really hard to find a cactus, that is so particular and at the same time simple to grow. With very little attention it will decorate your rooms in a truly unique way! Here are some tips for its cultivation: It prefers a bright location, avoid direct sunlight. Morning sunlight is excellent, until 12.00 / 13.00. Keep it at mild temperatures and never below 8 °C. It is recommended to shelter it during the winter period. Water moderately,only when the soil is completely dry. It is enough to water the plant once a week in spring and summer. Suspend watering in winter. The best soil is a well-draining one, even better if further enriched with inert materials such as pumice, sand or lapilli. They do not need frequent fertilization, it is sufficient to dilute the fertilizer with watering once a year.