Pachyphytum sp crest form
Echeveria agavoides cresting
Fasciation or cresting occurs when a plant develops a fan shaped flattened stem and growing point, resulting in a mass of crowded leaves which become distorted and over- lapping or in strangely elongated flowers at the end of the stem. It is often seen in daisy flowers and is not regarded as a desirable trait, though the summer annual Celosia 'Cockscomb' is a good example of where it has been selected and bred to look as such.
The cause of cresting is usually attributed to a number of factors such as hormonal imbalance at a cellular level or invasion of the plant system by a virus or bacteria.
In succulent plants it is considered unique and crested forms of some species are considered quite collectible.One of the best examples and well worth growing is the crest form of Echeveria 'Gilva' as the resulting plant swirls and undulates in the pot and the grey green leaves with pink winter tips is very becoming.
Crest forms of succulents make terrific low maintenance pot plants as they usually stay neat and compact and continue to spread out and mound or undulate as they grow. Perhaps the only down side to this form is that the tightly held leaves are more subject to rotting from excess water held within the leaves and resulting lack of air flow around the plant. Often you have to rescue a specimen by cutting away the dead sections and starting again but this is only really a problem in warm humid weather or at times of excessive rainfall.