Fasciation

Fasciation (pronounced /ˌfæʃiˈeɪʃən/, 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, instead becomes elongated perpendicularly to the direction of growth, thus producing flattened, ribbon-like, crested (or "cristate"), or elaborately contorted tissue.

[4] The bacterial phytopathogen Rhodococcus fascians has been demonstrated as one cause of fasciation, such as in sweet pea (Lathyrus odoratus) plants,[7] and in lilies (Lilium longiflorum),[8] but many fasciated plants have tested negative for the bacteria in studies,[9][better source needed] hence bacterial infection is not an exclusive causation.

Additional environmental factors that can cause fasciation include fungi, mite or insect attack and exposure to chemicals.

[10] Although fasciation is rare overall, it has been observed in over 100 vascular plant families,[11][better source needed] including members of the genera Acer, Aloe, Acanthosicyos, Cannabis, Celosia, Cycas, Delphinium, Digitalis, Echinacea, Echinopsis, Euphorbia, Forsythia, Glycine max (specifically, soybean plants),[12] Primula, Iochroma, Prunus, Salix, and many genera of the cactus family, Cactaceae.

[citation needed] Cresting results in undulating folds instead of the typical "arms" found on mature saguaro cactus.