Malformations may occur in all species of plants. Little is known of the origin of such abnormalities The phenomenon is referred to as fasciation.
The terminal or growing centre of a plant is composed of rapidly multiplying cells which constitute the meristem. In rare instances, a plant will develop meristems at a number of points on one, producing the phenomenon known as a monstrous form.
In other rare instances, the meristem widens into a line rather than a point, and this form is known as a cristate form or crest.
Insect damage to the growing centre may be one cause. Recent experiments have also proved thai radio-active soil usually causes fasciation.
Another phenomenon is that a monstrous oi cristate plant may suddenly again produce norma branches and shoots.
Such plants as Opunlia clavarioides cristata Opuntia cylindrica cristata, Cereus Peruvianas mon-strosus, Echinopsis tubiflora cristata, and Rebutic tmnuscula cristata are often seen in collections.