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Fasciation (pronounced / ˌ f æ ʃ i ˈ eɪ ʃ ə n /, from the Latin root meaning "band" or "stripe"), also known as cresting, is a relatively rare condition of abnormal growth in vascular plants in which the apical meristem (growing tip), which normally is concentrated around a single point and produces approximately cylindrical tissue ...
An example of the latter type is the aphid, which forms marble-sized galls on the leaf stems of cottonwood trees. While these galls have thin walls, they harbor entire colonies of aphids within. When the time is right, a slit appears on one side of the gall, allowing the aphids to escape as the slit's lips unfold.
Symptoms will often appear overnight, affecting many types of plants. Leaves and stems may turn black, and buds and flowers may be discoloured, and frosted blooms may not produce fruit. Many annual plants, or plants grown in frost free areas, can suffer from damage when the air temperature drops below 40 degrees Fahrenheit (4 degrees Celsius).
Secondary growth thickens the stem and roots, typically making them woody.Obstructions such as this metal post and stubs of limbs can be engulfed. In botany, secondary growth is the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems ...
Signs of Cryptomyzus ribis are domed blisters on the leaves of, mainly red and white currant bushes. Soon after the leaves open in the spring, the galls are yellow and turn red by the early summer. Leaves can also be crinkled, with a colony of yellow-greenish aphids living in the hairy depressions on the underside of the leaves.
Two of my favorite spring plants, almost entirely based upon their progression from bud to leaf, are beech trees and false hellebore.
The gall is a stalked, club-like smooth pouch (7−15 mm high) on the leaves of elm trees. Feeding inside the gall is a nymph and some wax. Partly formed galls are pale yellow patches with irregular lumpy projections on the top surface of the leaf. On the underside of the leaf, young galls may have a hairy opening. [6]
Burrs on a tree trunk in Norfolk, England. A burl (American English) or burr (British English) is a tree growth in which the grain has grown in a deformed manner. It is commonly found in the form of a rounded outgrowth on a tree trunk or branch that is filled with small knots from dormant buds. Burl formation is typically a result of some form ...