This is an example of fasciation involving the flowering parts of this Dodonaea shrub found on the TAFE campus.
Fasciation is a condition of plant growth in which the apical meristem (or growing tip - an area of undifferentiated plant cells found in buds and tips of roots, its main function to initiate growth in young plants at the tips of roots and shoots) becomes elongated perpendicular to the direction of growth. Normally, growth is focused around a singular point and produces cylindrical growth. In fasciated plants, the area of growth is flattened, fan shaped, ribbon-like or generally highly contorted. This can involve stem, root, fruit or flowerhead.
Causes include a genetic mutation in the cells, bacterial infection, mite or insect attack, chemical or mechanical damage. Usually it is benign and can be left alone if tolerated. Pruning affected areas may or may not remove the condition in that area of the plant.
Reference : Wikipedia
This type of growth abnormality is usually referred to as 'Witches broom' normally fasciation has a flattened stem appearance reminiscent of the flattened neck of a cobra snake. Some witches brooms can get to a large size, some meters in width. They have often been associated with mite infestations.
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