Fasciation (pronounced , from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

root meaning "band" or "stripe"), also known as cresting, is a relatively rare condition of abnormal growth in

vascular plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...

s 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. Fasciation may also cause plant parts to increase in weight and volume in some instances. The phenomenon may occur in the

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

, or flower head. Some plants are grown and prized aesthetically for their development of fasciation. Any occurrence of fasciation has several possible causes, including hormonal, genetic,

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

fungal A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

viral Viral means "relating to viruses" (small infectious agents). Viral may also refer to: Viral behavior, or virality Memetic behavior likened that of a virus, for example: * Viral marketing, the use of existing social networks to spread a marke ...

and environmental causes.

Cause

Fasciation can be caused by hormonal imbalances in the meristematic cells of plants, which are cells where growth can occur. Fasciation can also be caused by random

genetic mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitos ...

. Bacterial and viral infections can also cause fasciation. The bacterial

phytopathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

Rhodococcus fascians ''Rhodococcus fascians'' (known as ''Corynebacterium fascians'' until 1984) is a Gram positive bacterial phytopathogen that causes leafy gall disease. ''R. fascians'' is the only phytopathogenic member of the genus ''Rhodococcus''; its host ra ...

'' has been demonstrated as one cause of fasciation, such as in sweet pea (''

Lathyrus odoratus The sweet pea, ''Lathyrus odoratus'', is a flowering plant in the genus ''Lathyrus'' in the family Fabaceae (legumes), native to Sicily, southern Italy and the Aegean Islands. It is an annual climbing plant, growing to a height of , where suita ...

'') plants, but many fasciated plants have tested negative for the bacteria in studies, hence bacterial infection is not an exclusive causation. Additional environmental factors that can cause fasciation include fungi,

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

attack and exposure to chemicals. General damage to a plant's growing tip and exposure to cold and frost can also cause fasciation. Some plants, such as peas and cockscomb '' Celosia'', may inherit the trait. Genetic fasciation is not contagious, but infectious fasciation can be spread from infected plants to others from contact with wounds on infected plants, and from water that carries the bacteria to other plants.

Occurrence

Although fasciation is rare overall, it has been observed in over 100 vascular plant

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

, including members of the

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

'' Acer'', ''

Aloe ''Aloe'' (; also written ''Aloë'') is a genus containing over 650 species of flowering succulent plants.WFO (2022): Aloe L. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-4000001341. Accessed on: 06 Nov 2022 The most wid ...

'', ''

Acanthosicyos ''Acanthosicyos'' is a genus of thorny shrubs of the botanical family Cucurbitaceae, subfamily Cucurbitoideae. The genus name derives from the Greek words "''akantha''" for thorn and "''sykios''" for cucumber or gourd. Species Endemic to the Na ...

'', ''

Cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: ''Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternatively ...

'', '' Celosia'', '' Cycas'', '' Delphinium'', '' Digitalis'', ''

Echinacea ''Echinacea'' is a genus of herbaceous flowering plants in the daisy family. It has ten species, which are commonly called coneflowers. They are found only in eastern and central North America, where they grow in moist to dry prairies and ope ...

'', '' Euphorbia'', ''

Forsythia ''Forsythia'' , is a genus of flowering plants in the olive family Oleaceae. There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe. ''Forsythia'' – also one of the plant's common names – is ...

'', '' Glycine max'' (specifically,

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu an ...

plants), '' Primula'', '' Iochroma'', ''

Prunus ''Prunus'' is a genus of trees and shrubs, which includes (among many others) the fruits plums, cherries, peaches, nectarines, apricots, and almonds. Native to the North American temperate regions, the neotropics of South America, and the p ...

'', '' Salix'', and many genera of the

cactus A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

family,

Cactaceae A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

. Cresting results in undulating folds instead of the typical "arms" found on mature saguaro cactus. Some varieties of ''Celosia'' are raised especially for their dependably fasciated flower heads, for which they are called "cockscomb". The Japanese fantail willow ( ''Salix sachalinensis'' 'Sekka') is another plant that is valued for its fasciations.

Prevention

Fasciation that is caused by bacteria can be controlled by not using fasciated plants and disposing of fasciated material. Avoiding injury to plant bases and keeping them dry can reduce the spread of bacteria. Avoidance of grafting fasciated plants and the pruning of fasciated matter can also reduce the spread of bacteria.

Examples

File:Fasciation on a coneflower.jpg, An example of fasciation, or "cresting," on a

coneflower Coneflower is a common name of several genera of flowering plants: ;In the family Asteraceae *'' Dracopis'' *''Echinacea'' *''Rudbeckia'' *''Ratibida'' ;In the family Proteaceae * ''Isopogon'' See also *Cornflower ''Centaurea cyanus'', comm ...

(''Echinacea''). File:Double Dandelion.jpg, Fasciation leading to two fully formed flower heads on a dandelion. File:Digitalis Fasciation detail stem.jpg, Fasciation on '' Digitalis''. Note the larger thickened stem compared to the normal-sized flowering spike on the left. File:Fasciated Flowering Cherry branch.JPG, Fasciation on a flowering

cherry A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The nam ...

(''Prunus'') tree File:PSM V42 D335 Asparagus fasciation.jpg, Asparagus (''Asparagus officinalis'') fasciation. Note the flattened state of the stem. Image published 1893. File:Fasciated Dandelion 01.JPG, Common dandelion displaying both regular (upper right) and fasciated (center) flowers. File:Fasciated Lilac.JPG, Fasciation on a

lilac ''Syringa'' is a genus of 12 currently recognized species of flowering plant, flowering woody plants in the olive family or Oleaceae called lilacs. These lilacs are native to woodland and scrub from southeastern Europe to eastern Asia, and wid ...

shrub. File:Fasciated California Bluebell (Phacelia campanularia).jpg, Fasciation on a '' Phacelia campanularia'' or California bluebell wildflower. File:Fasciated Showy Daisy July 3 2016.jpg, Fasciated showy daisy (''Erigeron speciosus''). File:Fasciated Crookneck Squash.jpg, Fasciated Crookneck Squash File:Dandelion Fascination.jpg, alt=Pictured is common dandelion with multiple fully formed flower heads and a notably wide stem joined in fascination., Fasciation seen on common dandelion File:Geranium palustre fasciation.jpg, alt=Picture showing a regular flower of Geranium palustre on the left, and a fasciated one with a double amount of petals and two pistils., Regular (left) and fasciated (right)

geranium ''Geranium'' is a genus of 422 species of annual, biennial, and perennial plants that are commonly known as geraniums or cranesbills. They are found throughout the temperate regions of the world and the mountains of the tropics, but mostly in ...

flowers

References

External links

* {{cite web , url=http://www.merriam-webster.com/dictionary/fasciation , title=Definition of "Fasciation" , publisher=Merriam-Webster Dictionary , accessdate=July 6, 2012 Botany Plant morphology