Fasciation

From an Encyclopedia:

Fasciation (or cresting) is a condition of plant growth in which the apical meristem, normally concentrated around a single point, producing approximately cylindrical tissue, becomes elongated perpendicularly to the direction of growth, producing flattened, ribbon-like, crested, or elaborately contorted tissue. The phenomenon may occur in the stem, root, fruit, or flower head. Fasciation can be caused by a mutation in the meristematic cells, bacterial infection, mite or insect attack, or chemical or mechanical damage. Some plants may inherit the trait.

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In plain English: It is not uncommon for an orchid grower to find deformed-looking flowers, or a stem that appears to be deformed. That odd-looking growth is called “Fasciation”. Some believe that “Fasciation”, is caused by a hormonal imbalance and that imbalance could be either a random genetic mutation or induced by external environmental factors,such as: bacteria, fungi, insects, frost, chemical spraying, etc.

Some plants may exhibit flowers that show fasciation only once. I believe, that in this case, bacteria, fungi, insects, frost, chemical spraying, etc. caused the imbalance. What are the chances for the same fungi to attack the same plant two or three years in a row?

We know viruses work "inside" plants and interfere with their DNA. DNA changes may be the real cause of the genetic mutation that causes "Fasciation". Once the genetic code has changed, the plant has changed and its flowers show the same Fasciation year after year.

It is a fact that Fasciation itself is not contagious and does not spread. Plants that show Fasciation are very popular and expensive in Asia. Orchids that show Fasciation are rejected in Australia, Europe and America.

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From: ORCHIDS OF ASIA. COPIED FROM: ORCHIDS OF ASIA. 3rd Edition. By Teoh Eng Soon. Pages: 305-306 (A very good book)

"Mutation sometimes manifests as fasciations, the condition where multiple petals and/or lips are crowded together on a flower. The term is derived from the Latin “fasciculum”, meaning “a bundle”. The phenomenon is not confined to orchids". "Caused by splitting and proliferation of apical meristems, the process can be triggered by growth hormones, chemicals, radiation, viruses and other infectious agents. Two oriental Cymbidiums (Cym. sinensite and Cym. goeringii) are prized for their fasciated flowers.

In his discussion of the topic in Orchids (July 2001), the Magazine of the American Orchid Society, Carl Withner mentioned that a Belgian horticulturist crossed two peloric forms of Cattleya labiata in the 1920's. After two or three generations, he obtained Cattleya flowers with 15-20 petals but without a lip.

Fasciated flowers sometimes appear within an inflorescence of peloric Phalaenopsis. Such mutations are rarely attractive and have not been traditionally admired in the West. However, recently, the American Orchid Society gave a "Judges’ Commendation Award” to recognise that this trait that might be worth exploring".

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Peloric (from Greek Peloros = Monstrous (Actually it is "Pelorios" and means "Huge", "Gigantic")) is a mutation. Fasciation under a different name if you like. I guess "Peloric" sound more glamorous.

Peloric flowers, some say, show a different symetry. Orchid flowers are zygomorphic (can be divided into two mirror-image half). Peloric orchid flowers are actinomorphic (cannot be divided into two mirror-image halfs). Like all fasciated flowers, "Peloric" flowers are found predominantly in Phalaenopsis, Cymbidiums and Dendrobiums.

As I understand it, Cymbidium mosaic virus has been frequently found in Cymbidium Peloric mutations.