Fasciation, or cresting, is a rare of abnormal growth in vascular plants where the growing tips becomes elongated perpendicularly to the direction of growth, producing flattened, ribbon-like, crested or contorted tissue. Fasciation can also cause plant parts to increase in weight and volume. It can happen in stems, roots, fruit or flower heads. Some plants are grown and prized for their development of exotic fasciation. It has several possible causes including hormonal, genetic, bacterial, fungal, viral, insect or mite attacks, exposure to chemicals, physical damage to a plant’s growing tip, weather changes and extremes and other environmental impacts.
Fasciation of Texas Mountain Laurel Flower
Some plants, such as peas and cockscomb (Celosia), can inherit the trait. It is not contagious but pathogens that cause some fasciations can be spread from infected plants to others.