Fasciation

Fasciation

(fascia (Latin)- to fuse)

Cristate and montrose growth is a phenomenon that has always fascinated plant collectors. Cristate forms occur when plant's meristerm or single growing point begins to multiply erratically elongating the growing tip. The mechanism behind fasciation is not well understood. A variety of reasons have been noted to cause plant fasciation, but its development is still poorly understood. Genetics, mechanical damage, sudden cold, insect damage, bacteria, herbicides, and viruses have all been declared as causes for this mutation.

Fasciations are widespread throughout the plant kingdom with reports in over 86 genera. The mutation is not limited to stems as it can occur in fruits, flowers, and roots as well. While linear fasciation is most common (crest forming) bifurcated fasciations, multiradiate fasciations, and ring fasciations are often found. In bifurcated fasciations the affected part of the plant will split off and form a 'Y' shape with excessive meristems along both offsets. Multiradiate fasciations cause the affected part to split off into three or more short branches that then form extra growing points. Ring Fasciations cause the growing point to fuse and form a funnel shape. Montrose plants can occur as well in which many growing points fasciate at once, forming an overall bumpy gnarly shape as each part of the plant fights for apical dominance.

While fasciation is not contagious and does not spread from plant to plant within a garden, fasciation can be inherited in certain species through the mutation of flowers and fruit. The cockscomb celosia (Celosia argentea var cristata) is an excellent example of a plant with inherited fasciation. Keep in mind that not all plants will inherit faciation from seed, so cuttings are still the best method for reproduction. Fasciated plants are often identified by the descriptive cultivar names of `torulosa' and `monstora'.

It is not known if fasciations in most woody plants are inherited. It is known, that the tendency toward fasciation is transmissible by budding and grafting once the woody plant develops a fasciation. Fasciated woody plants are often referred to as Witches Brooms, and most dwarf conifers are developed from these mutations.