fasciated

Fasciation is a condition in plants in which the growth axis becomes broadened and flattened, producing elongated, ribbon-like, or fan-shaped stems and multiple apical growing points. The result is a visually irregular, crested, or contorted morphology rather than normal, cylindrical stems. Fasciation is a symptom or outcome of meristematic overgrowth rather than a distinct disease itself.

Causes are varied and often multifactorial. Genetic mutations can predispose plants to fasciation. Environmental stresses such as nutrient imbalance, temperature extremes, or mechanical damage can trigger it. Pathogens including certain bacteria (such as Corynebacterium fascians), phytoplasmas, and some fungi have been associated with fasciation, while in many instances the cause remains undetermined.

Morphology varies widely. Affected stems may be flattened, crested, or fan-shaped, with several parallel ridges or folds and multiple meristems producing several axes. Fasciation can occur on the main stem or on branches, inflorescences, and even roots, and is observed in diverse plant groups, including ornamentals, cacti, and trees.

Fasciation rarely kills a plant but can reduce vigor, flower or fruit production, or uniformity. In ornamentals, fasciated forms are valued; in crops, it is usually undesirable. Management focuses on removing infected tissue if a pathogen is involved, avoiding wounding, and maintaining overall plant health. Because fasciation can be genetic, propagating from fasciated tissue can perpetuate the form.

The term fasciation derives from the Latin fascia, meaning a band or stripe, describing the ribbon-like appearance.