Dahlia Sin'felle
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''Dahlia'' ( , ) is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of bushy,
tuberous Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reprodu ...
,
herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...
perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
plants native to Mexico and Central America. Dahlias are members of the
Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...
(synonym name: Compositae) family of
dicotyledon The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...
ous plants, its relatives include the
sunflower The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the pr ...
, daisy,
chrysanthemum Chrysanthemums ( ), sometimes called mums or chrysanths, are flowering plants in the Asteraceae family. They are native to East Asia and northeastern Europe. Most species originate from East Asia, and the center of diversity is in China. Co ...
, and
zinnia ''Zinnia'' is a genus of plants of the tribe Heliantheae within the family Asteraceae. They are native to scrub and dry grassland in an area stretching from the Southwestern United States to South America, with a centre of diversity in Mexic ...
. There are 49
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of dahlia, with flowers in almost every hue (except blue), with
hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...
s commonly grown as garden plants. Dahlias were known only to the
Aztecs The Aztecs ( ) were a Mesoamerican civilization that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec people included different ethnic groups of central Mexico, particularly those groups who spoke the ...
and other southern North American peoples until the
Spanish conquest The Spanish Empire, sometimes referred to as the Hispanic Monarchy or the Catholic Monarchy, was a colonial empire that existed between 1492 and 1976. In conjunction with the Portuguese Empire, it ushered in the European Age of Discovery. It ...
, after which the plants were brought to Europe. The tubers of some varieties are of medicinal and dietary value to humans because they contain
inulin Inulins are a group of naturally occurring polysaccharides produced by many types of plants, industrially most often extracted from chicory. The inulins belong to a class of dietary fibers known as fructans. Inulin is used by some plants as a ...
, a polymer of the fruit sugar,
fructose Fructose (), or fruit sugar, is a Ketose, ketonic monosaccharide, simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and gal ...
.


Description

Dahlias are perennial plants with tuberous roots. They are not frost hardy, and require protection from frost if grown in regions with cold winters. While some have herbaceous stems, others have stems which lignify in the absence of secondary tissue and resprout following winter dormancy, allowing further seasons of growth. As members of the family
Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...
, dahlias have composite flower heads called capitula that are composed of multiple
floret This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...
s arranged in a central disc with surrounding petal-like rays. Each floret is a flower in its own right. The modern name Asteraceae comes from the type genus ''
Aster Aster or ASTER may refer to: Biology * ''Aster'' (genus), a genus of flowering plants ** List of ''Aster'' synonyms, other genera formerly included in ''Aster'' and still called asters in English * Aster (cell biology), a cellular structure shap ...
'' and the
Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
word for "star", referring to the appearance of a star with surrounding rays. The stems are leafy, ranging in height from as low as to more than . Flower forms are variable, with one head per stem; these can be as small as in diameter or up to ("dinner plate"). The majority of species do not produce scented flowers. Like most plants that do not attract
pollinating Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or butterflies; birds ...
insects through scent, they are brightly colored, displaying most hues, with the exception of blue. The great variety in species results from garden dahlias being
octoploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...
s, having eight sets of homologous
chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...
s. In addition, dahlias also contain many
transposons A transposable element (TE), also transposon, or jumping gene, is a type of mobile genetic element, a nucleic acid sequence in DNA that can change its position within a genome. The discovery of mobile genetic elements earned Barbara McClinto ...
—genetic pieces that move from place to place upon an
allele An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...
—which contributes to their manifesting such great diversity.


Taxonomy


Taxonomic history


Early history

Spaniards reported finding the plants growing in Mexico in 1525, but the earliest known description is by Francisco Hernández, physician to Philip II, who was ordered to visit Mexico in 1570 to study the "natural products of that country". They were used as a source of food by the indigenous peoples, who both gathered wild specimens and cultivated crops.Harvard Arboretum
/ref>Katz, Solomon H.; Weaver, William Woys Weaver, Encyclopedia of Food and Culture, The Gale Group, New York, 2002. The indigenous peoples variously identified the plants as "Chichipatl" (
Toltecs The Toltec culture () was a Pre-Columbian era, pre-Columbian Mesoamerican culture that ruled a state centered in Tula (Mesoamerican site), Tula, Hidalgo (state), Hidalgo, Mexico, during the Epiclassic and the early Post-Classic period of Mesoam ...
) and "Acocotle" or "Cocoxochitl" (
Aztecs The Aztecs ( ) were a Mesoamerican civilization that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec people included different ethnic groups of central Mexico, particularly those groups who spoke the ...
). From Hernandez's perception of
Nahuatl Nahuatl ( ; ), Aztec, or Mexicano is a language or, by some definitions, a group of languages of the Uto-Aztecan language family. Varieties of Nahuatl are spoken by about Nahuas, most of whom live mainly in Central Mexico and have smaller popul ...
to
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many countries in the Americas **Spanish cuisine **Spanish history **Spanish culture ...
(through various other translations) the word is "water cane", "water pipe", "water pipe flower", "hollow stem flower", or "cane flower", all referring to the hollow plant stems. Hernandez described two varieties of dahlias (the pinwheel-like ''
Dahlia pinnata ''Dahlia pinnata'' (''D.'' × ''pinnata'') is a species in the genus ''Dahlia'', family Asteraceae, with the common name garden dahlia. It is the type species of the genus and is widely cultivated. Description ''Dahlia pinnata'' is a perennial ...
'' and the huge ''Dahlia imperialis'') as well as other medicinal plants of New Spain. Francisco Dominguez, an Hidalgo gentleman who accompanied Hernandez on part of his seven-year study, made a series of drawings to supplement the four volume report. Three of his drawings showed plants with flowers: two resembled the modern bedding dahlia, and one resembled the species '' Dahlia merckii''; all displayed a high degree of doubleness. In 1578, a manuscript titled ''Nova Plantarum, Animalium et Mineralium Mexicanorum Historia'', was sent back to the
Escorial El Escorial, or the Royal Site of San Lorenzo de El Escorial (), or (), is a historical residence of the king of Spain located in the town of San Lorenzo de El Escorial, up the valley ( road distance) from the town of El Escorial and about n ...
in Madrid. It was translated into Latin by Francisco Ximenes in 1615. In 1640, Francisco Cesi, President of the ''Academia dei Lincei'' of Rome, bought the Ximenes translation and, after annotating it, published it in 1649–1651 as two volumes, ''Rerum Medicarum Novae Hispaniae Thesaurus Seu Nova Plantarium, Animalium et Mineralium Mexicanorum Historia''. The original manuscripts were destroyed in a fire in the mid-1600s.


European introduction

In 1787, the French botanist
Nicolas-Joseph Thiéry de Menonville Nicolas-Joseph Thiéry de Menonville (18 June 1739 in Saint-Mihiel, France – 1780 in Port-au-Prince, Saint-Domingue), ''avocat'' at the ''Parlement of Paris'', was a French botanist who volunteered to be sent to Mexico in 1776 to steal the Car ...
, sent to Mexico to steal the
cochineal The cochineal ( , ; ''Dactylopius coccus'') is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. A primarily sessility (motility), sessile parasitism, parasite native to tropical and subtropical Sout ...
insect valued for its scarlet dye, reported the strangely beautiful flowers he had seen growing in a garden in Oaxaca. In 1789,
Vicente Cervantes Vicente or Vincente de Cervantes (1755 in Ledrada – 1829 in Mexico) was a notable Spanish and Mexican physician and botanist. Background Don Vicente Cervantes was a contemporary of Martín Sessé y Lacasta and corresponded with Jean-Louis Ber ...
, director of the Botanical Garden at Mexico City, sent "plant parts" to Abbe
Antonio José Cavanilles Antonio José Cavanilles (16 January 1745 – 5 May 1804) was a leading Spanish taxonomic botanist, artist and one of the most important figures in the 18th century period of Enlightenment in Spain. Cavanilles is most famous for his 2-vol ...
, director of the Royal Gardens of Madrid. Cavanilles flowered one plant that same year, then the second one a year later. In 1791 he called the new growths "Dahlia" for
Anders Dahl Anders (or Andreas) Dahl (17 March 1751 – 25 May 1789) was a Swedes, Swedish botanist and student of Carl Linnaeus. The dahlia flower is named after him. Early life and education Andreas (Anders) Dahl was the son of Christoffer Dahl, a preac ...
. The first plant was called ''Dahlia pinnata'' after its
pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...
foliage; the second, ''Dahlia rosea'' for its rose-purple color. In 1796, from the parts sent by Cervantes, Cavanilles flowered a third plant, which he named ''
Dahlia coccinea ''Dahlia coccinea'' is a species of flowering plant in the daisy family Asteraceae. Its common name is red dahlia, although the flowers can be orange or occasionally yellow, as well as the more common red. The species is native to Mexico but has ...
'' for its scarlet color. In 1798, Cavanilles sent ''D. pinnata'' seeds to
Parma Parma (; ) is a city in the northern Italian region of Emilia-Romagna known for its architecture, Giuseppe Verdi, music, art, prosciutto (ham), Parmesan, cheese and surrounding countryside. With a population of 198,986 inhabitants as of 2025, ...
, Italy. That year, the Marchioness of Bute, wife of the Earl of Bute, the English Ambassador to Spain, obtained a few seeds from Cavanilles and sent them to
Kew Gardens Kew Gardens is a botanical garden, botanic garden in southwest London that houses the "largest and most diverse botany, botanical and mycology, mycological collections in the world". Founded in 1759, from the exotic garden at Kew Park, its li ...
, where they flowered but were lost after two to three years.Dean, Richard, The dahlia: its history and cultivation, Macmillan, 1897, p.5. In the following years Madrid sent seeds to Berlin and Dresden in Germany, and to Turin and Thiene in Italy. In 1802, Cavanilles sent tubers of "these three" (''D. pinnata, D. rosea, D. coccinea'') to Swiss botanist
Augustin Pyramus de Candolle Augustin Pyramus (or Pyrame) de Candolle (, , ; 4 February 17789 September 1841) was a Swiss people, Swiss botany, botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple ...
at University of Montpelier in France, Andre Thouin at the
Jardin des Plantes The Jardin des Plantes (, ), also known as the Jardin des Plantes de Paris () when distinguished from other ''jardins des plantes'' in other cities, is the main botanical garden in France. Jardin des Plantes is the official name in the present da ...
in Paris and Scottish botanist
William Aiton William Aiton (17312 February 1793) was a Scotland, Scottish botanist. Aiton was born near Hamilton, Scotland, Hamilton. Having been regularly trained to the profession of a gardener, he travelled to London in 1754, and became assistant to Phi ...
at Kew Gardens. That same year, John Fraser, English nurseryman and later botanical collector to the Czar of Russia, brought '' D. coccinea'' seeds from Paris to the Apothecaries Gardens in England, where they flowered in his greenhouse a year later, providing ''Botanical Magazine'' with an illustration. In 1804, a new species, ''Dahlia sambucifolia'', was successfully grown at
Holland House Holland House, originally known as Cope Castle, was an early Jacobean architecture, Jacobean country house in Kensington, London, situated in a country estate that is now Holland Park. It was built in 1605 by the diplomat Sir Walter Cope. The b ...
, Kensington. Whilst in Madrid in 1804, Lady Holland was given either dahlia seeds or tubers by Cavanilles. She sent them back to England, to Lord Holland's librarian at Holland House, who successfully raised the plants and produced two double flowers a year later. The plants raised in 1804 did not survive; new stock was brought from France in 1815. In 1824, Lord Holland sent his wife a note containing the following verse:
The dahlia you brought to our isle
Your praises for ever shall speak;
Mid gardens as sweet as your smile,
And in colour as bright as your cheek.
In 1805, German naturalist
Alexander von Humboldt Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 1769 – 6 May 1859) was a German polymath, geographer, natural history, naturalist, List of explorers, explorer, and proponent of Romanticism, Romantic philosophy and Romanticism ...
sent more seeds from Mexico to Aiton in England, Thouin in Paris, and
Christoph Friedrich Otto Christoph Friedrich Otto (4 December 1783 – 7 December 1856) was a German gardener and botanist. He was born in Schneeberg, Saxony. From 1805 to 1843 he was inspector of the Botanical Garden in Berlin. Together with Albert Gottfried Dietric ...
, director of the
Berlin Botanical Garden The Berlin Botanic Garden and Botanical Museum () is a botanical garden in the locality of the borough of , Berlin, Germany. Constructed between 1897 and 1910 under the guidance of architect Adolf Engler, it has an area of and over 20,000 di ...
. More significantly, he sent seeds to botanist
Carl Ludwig Willdenow Carl Ludwig Willdenow (22 August 1765 – 10 July 1812) was a German botanist, pharmacist, and plant Taxonomy (biology), taxonomist. He is considered one of the founders of phytogeography, the study of the geographic distribution of plants. ...
in Germany. Willdenow now reclassified the rapidly growing number of species, changing the genus from ''Dahlia'' to ''Georgina''; after naturalist
Johann Gottlieb Georgi Johann Gottlieb Georgi (31 December 1729 – 27 October 1802) was a German-Russian botanist, naturalist and geographer. A native of Pomerania, Georgi accompanied both Johan Peter Falk and Peter Simon Pallas on their respective journeys through S ...
. He combined the Cavanilles species ''D. pinnata'' and ''D. rosea'' under the name of ''Georgina variabilis''; ''D. coccinea'' was still held to be a separate species, which he renamed ''Georgina coccinea''.


Classification

Since 1789 when Cavanilles first flowered the dahlia in Europe, there has been an ongoing effort by many growers, botanists and taxonomists, to determine the development of the dahlia to modern times. At least 85 species have been reported: approximately 25 of these were first reported from the wild; the remainder appeared in gardens in Europe. They were considered
hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...
s, the results of crossing between previously reported species, or developed from the seeds sent by Humboldt from Mexico in 1805, or perhaps from some other undocumented seeds that had found their way to Europe. Several of these were soon discovered to be identical with earlier reported species, but the greatest number are new varieties.
Morphological variation Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
is highly pronounced in the dahlia.
William John Cooper Lawrence William is a masculine given name of Germanic languages, Germanic origin. It became popular in England after the Norman Conquest, Norman conquest in 1066,All Things William"Meaning & Origin of the Name"/ref> and remained so throughout the Middle ...
, who hybridized hundreds of families of dahlias in the 1920s, stated: "I have not yet seen any two plants in the families I have raised which were not to be distinguished one from the other. Constant reclassification of the 85 reported species has resulted in a considerably smaller number of distinct species, as there is a great deal of disagreement today between systematists over classification. In 1829, all species growing in Europe were reclassified under an all-encompassing name of ''D. variabilis, Desf.'', though this is not an accepted name. Through the interspecies cross of the Humboldt seeds and the Cavanilles species, 22 new species were reported by that year, all of which had been classified in different ways by several different taxonomists, creating considerable confusion as to which species was which. As of now Dahlias are classified into 15 different species by botanist
Liberty Hyde Bailey Liberty Hyde Bailey (March 15, 1858 – December 25, 1954) was an American Horticulture, horticulturist and reformer of rural life. He was cofounder of the American Society for Horticultural Science.Makers of American Botany, Harry Baker Humphrey ...
. In 1830 William Smith suggested that all dahlia species could be divided into two groups for color, red-tinged and purple-tinged. In investigating this idea Lawrence determined that with the exception of ''D. variabilis'', all dahlia species may be assigned to one of two groups for flower-colour: Group I (ivory-magenta) or Group II (yellow-orange-scarlet).


Modern classification

The genus ''Dahlia'' is situated in the
Asteroideae Asteroideae is a subfamily of the plant family Asteraceae. It contains about 70% of the species of the family. It consists of several tribes, including Astereae, Calenduleae, Eupatorieae, Gnaphalieae, Heliantheae, Senecioneae and Tageteae. ...
subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...
of the
Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...
, in the
Coreopsideae Coreopsideae is a tribe of flowering plants belonging to the Asteroideae subfamily. It includes widely cultivated genera such as ''Coreopsis,'' after which the tribe is named, as well as ''Cosmos'' and ''Dahlia''. A similar group has been recogn ...
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...
. Within that tribe it is the second largest genus, after ''Coreopsis'', and appears as a well defined
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
within the Coreopsideae.


Subdivision


Infrageneric subdivision

Sherff (1955), in the first modern taxonomy described three sections for the 18 species he recognised, ''Pseudodendron'', ''Epiphytum'' and ''Dahlia''. By 1969 Sørensen recognised 29 species and four sections by splitting off ''Entemophyllon'' from section ''Dahlia''. By contrast Giannasi (1975) using a
phytochemical Phytochemicals are naturally-occurring chemicals present in or extracted from plants. Some phytochemicals are nutrients for the plant, while others are metabolites produced to enhance plant survivability and reproduction. The fields of ext ...
analysis based on
flavonoids Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...
, reduced the genus to just two sections, ''Entemophyllon'' and ''Dahlia'', the latter having three subsections, ''Pseudodendron'', ''Dahlia'', and ''Merckii''. Sørensen then issued a further revision in 1980, incorporating subsection ''Merckii'' in his original section ''Dahlia''. When he described two new species in the 1980s ('' Dahlia tubulata'' and '' D. congestifolia''), he placed them within his existing sections. A further species, '' Dahlia sorensenii'' was added by Hansen and Hjerting in (1996). At the same time they demonstrated that ''
Dahlia pinnata ''Dahlia pinnata'' (''D.'' × ''pinnata'') is a species in the genus ''Dahlia'', family Asteraceae, with the common name garden dahlia. It is the type species of the genus and is widely cultivated. Description ''Dahlia pinnata'' is a perennial ...
'' should more properly be designated ''D. x pinnata''. ''D. x pinnata'' was shown to actually be a variant of ''D. sorensenii'' that had acquired hybrid qualities before it was introduced to Europe in the sixteenth century and formally named by Cavanilles. The original wild ''D. pinnata'' is presumed extinct. Further species continue to be described, Saar (2003) describing 35 species. However separation of the sections on morphological, cytological, and biochemical criteria has not been entirely satisfactory. To date these sectional divisions have not been fully supported
phylogenetically In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...
, which demonstrate only section ''Entemophyllon'' as a distinct sectional
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
. The other major grouping is the core ''Dahlia'' clade (CDC), which includes most of the section ''Dahlia''. The remainder of the species occupy what has been described as the variable root clade (VRC) which includes the small section ''Pseudodendron'' but also the monotypic section ''Epiphytum'' and a number of species from within section ''Dahlia''. Outside of these three clades lie ''D. tubulata'' and ''D. merckii'' as a
polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...
. Horticulturally the sections retain some usage, section ''Pseudodendron'' being referred to as 'Tree Dahlias', ''Epiphytum'' as the 'Vine Dahlia'. The remaining two herbaceous sections being distinguished by their
pinnules A leaflet (occasionally called foliole) in botany is a leaf-like part of a compound leaf. Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. Co ...
, opposing (''Dahlia'') or alternating (''Entemophyllon'').


= Sections

= Sections (including chromosome numbers), with geographical distribution; * ''Epiphytum'' Sherff (2n = 32) **10 m tall climber with aerial roots 5 cm thick and up to more than 20 m long; pinnules opposite ** 1 species, ''D. macdougallii'' Sherff ** Mexico: Oaxaca * ''Entemophyllon'' P. D. Sorensen (2n = 34) ** 6 species ** Mexico: Hidalgo, Nuevo León, Tamaulipas, Querétaro, Durango, San Luis Potosí * ''Pseudodendron'' P. D. Sorensen (2n = 32) ** 3 species + ''D. excelsa'' of uncertain identity ** Mexico: Chiapas, Guerrero, Jalisco, Michoacan, Oaxaca, and Costa Rica, El Salvador, Guatemala & Colombia * ''Dahlia'' (2n = 32, 36 or 64) ** 24 species ** Mexico: Distrito Federal, Guerrero, Hidalgo, Morelos, Nuevo León, Puebla, San Luis Potosí, Tamaulipas, Veracruz, Oaxaca, Puebla, Chiapas, México, Huehuetenango, Chihuahua, Durango, Michoacan & Guatemala Only ''Pseudodendron'' ('' D. imperialis'') and ''Dahlia'' (''D. australis'', ''D. coccinea'') occur outside Mexico.


=Species

= There are currently 42 accepted species in the genus ''Dahlia'' but new species continue to be described.


Etymology

The naming of the plant itself has long been a subject of some confusion. Many sources state that the name "Dahlia" was bestowed by the pioneering Swedish botanist and taxonomist
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
to honor his late student,
Anders Dahl Anders (or Andreas) Dahl (17 March 1751 – 25 May 1789) was a Swedes, Swedish botanist and student of Carl Linnaeus. The dahlia flower is named after him. Early life and education Andreas (Anders) Dahl was the son of Christoffer Dahl, a preac ...
, author of ''Observationes Botanicae''. However, Linnaeus died in 1778, more than eleven years before the plant was introduced into Europe in 1789, so while it is generally agreed that the plant was named in 1791 in honor of Dahl, who had died two years before, Linnaeus could not have been the one who did so. It was probably Abbe Antonio Jose Cavanilles, Director of the Royal Gardens of Madrid, who should be credited with the attempt to scientifically define the genus, since he not only received the first specimens from Mexico in 1789, but named the first three species that flowered from the cuttings. Regardless of who bestowed it, the name was not so easily established. In 1805, German botanist
Carl Ludwig Willdenow Carl Ludwig Willdenow (22 August 1765 – 10 July 1812) was a German botanist, pharmacist, and plant Taxonomy (biology), taxonomist. He is considered one of the founders of phytogeography, the study of the geographic distribution of plants. ...
, asserting that the genus ''Dahlia'' Thunb. (published a year after Cavanilles's genus and now considered a synonym of ''
Trichocladus ''Trichocladus'' is a genus of flowering plants in the family Hamamelidaceae, consisting of shrubs or small trees. The distinguishing features of the genus ''Trichocladus'' are as follows: *Branches and leaves are often covered in dense, velvet-l ...
'') was more widely accepted, changed the plants' genus from ''Dahlia'' to ''Georgina'' (after the
German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...
-born naturalist
Johann Gottlieb Georgi Johann Gottlieb Georgi (31 December 1729 – 27 October 1802) was a German-Russian botanist, naturalist and geographer. A native of Pomerania, Georgi accompanied both Johan Peter Falk and Peter Simon Pallas on their respective journeys through S ...
, a professor at the Imperial Academy of Sciences of
St. Petersburg Saint Petersburg, formerly known as Petrograd and later Leningrad, is the second-largest city in Russia after Moscow. It is situated on the River Neva, at the head of the Gulf of Finland on the Baltic Sea. The city had a population of 5,601, ...
,
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
). He also reclassified and renamed the first three species grown, and identified, by Cavanilles. It was not until 1810, in a published article, that he officially adopted the Cavanilles's original designation of ''Dahlia''. However, the name ''Georgina'' still persisted in Germany for the next few decades. In Russian, it is still named Georgina ().


Distribution and habitat

''Dahlia'' is found predominantly in
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
, but some species are found ranging as far south as northern
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. '' D. australis'' occurs at least as far south as southwestern
Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...
, while ''D. coccinea'' and ''D. imperialis'' also occur in parts of
Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...
and northern South America. ''Dahlia'' is a genus of the uplands and mountains, being found at elevations between , in what has been described as a " pine–oak woodland" vegetative zone. Most species have limited ranges scattered throughout many mountain ranges in Mexico


Ecology

The most common pollinators are bees and small beetles.


Pests and diseases

Slugs Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a sma ...
and
snails A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...
are serious pests in some parts of the world, particularly in spring when new growth is emerging through the soil.
Earwigs Earwigs make up the insect order Dermaptera. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cerci, a pair of forceps-like pincers on their abdomen, and membranous wings folde ...
can also disfigure the blooms and foliage. The other main pests likely to be encountered are
aphids Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...
(usually on young stems and immature flower buds), red spider mite (causing foliage mottling and discolouration, worse in hot and dry conditions) and
capsid bug The Miridae are a large and diverse insect family at one time known by the Synonym (taxonomy), taxonomic synonym Capsidae. Species in the family may be referred to as capsid bugs or "mirid bugs". Common names include plant bugs, leaf bugs, and g ...
s (resulting in contortion and holes at growing tips). Diseases affecting dahlias include
powdery mildew Powdery mildew is a fungus, fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of Ascomycota, ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant disea ...
, grey mould (''
Botrytis cinerea ''Botrytis cinerea'' is a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes. In viticulture, it is commonly known as "botrytis bunch rot"; in horticulture, it is usually called "grey mould" ...
''),
verticillium ''Verticillium'' is a genus of fungi in the division Ascomycota, and are an anamorphic form of the family Plectosphaerellaceae. The genus used to include diverse groups comprising saprobes and parasites of higher plants, insects, nematodes, mol ...
wilt, dahlia smut (''Entyloma calendulae'' f. ''dahliae''),
phytophthora ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species cause economic losses on crops worldwide, as well as environmental dam ...
and some plant viruses. Dahlias are a source of food for the
larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...
e of some
Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...
species including
angle shades The angle shades (''Phlogophora meticulosa'') is a moth of the family Noctuidae. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. It is distributed throughout Europe as far east as the Urals and a ...
,
common swift The common swift (''Apus apus'') is a medium-sized bird, superficially similar to the barn swallow or Common house martin, house martin but somewhat larger, though not stemming from those passerine species, being in the order Apodiformes. The re ...
,
ghost moth The ghost moth or ghost swift (''Hepialus humuli'') is a moth of the family Hepialidae. It is common throughout Europe, except for the far south-east. Female ghost moths are larger than males, and exhibit sexual dimorphism with their differenc ...
and
large yellow underwing The large yellow underwing (''Noctua pronuba'') is a moth, the type species for the family Noctuidae. It is an abundant species throughout the Palearctic realm, one of the most common and most familiar moths of the region. In some years the speci ...
.


Cultivation

Dahlias grow naturally in climates that do not experience frost (the tubers are hardy to
USDA Zone A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most widely ...
8). Consequently they are not adapted to withstand sub-zero temperatures. However, their tuberous nature enables them to survive periods of
dormancy Dormancy is a period in an organism's Biological life cycle, life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolism, metabolic activity and therefore helps an organism to conserv ...
, and this characteristic means that gardeners in temperate climates with frosts can grow dahlias successfully, provided the tubers are lifted from the ground and stored in cool yet frost-free conditions during the winter. Planting the tubers quite deep () also provides some protection. When in active growth, modern dahlia hybrids perform most successfully in well-watered yet free-draining soils, in situations receiving plenty of sunlight. Taller cultivars usually require some form of staking as they grow, and all garden dahlias need deadheading regularly, once flowering commences.


Horticultural classification

Horticulturally the garden dahlia is usually treated as the
cultigen A cultigen (), or cultivated plant, is a plant that has been deliberately altered or selected by humans, by means of genetic modification, graft-chimaeras, plant breeding, or wild or cultivated plant selection. These plants have commercial val ...
''D. variabilis'' hort., which while being responsible for thousands of cultivars has an obscure taxonomic status.


History

The inappropriate term ''D. variabilis'' is often used to describe the cultivars of ''Dahlia'' since the correct parentage remains obscure, but probably involves ''
Dahlia coccinea ''Dahlia coccinea'' is a species of flowering plant in the daisy family Asteraceae. Its common name is red dahlia, although the flowers can be orange or occasionally yellow, as well as the more common red. The species is native to Mexico but has ...
''. In 1846 the Caledonia Horticultural Society of
Edinburgh Edinburgh is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. The city is located in southeast Scotland and is bounded to the north by the Firth of Forth and to the south by the Pentland Hills. Edinburgh ...
offered a prize of 2,000 pounds to the first person succeeding in producing a blue dahlia. This has to date not been accomplished. While dahlias produce
anthocyanin Anthocyanins (), also called anthocyans, are solubility, water-soluble vacuole, vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart named a chemical compou ...
, an element necessary for the production of the blue, to achieve a true blue color in a plant, the anthocyanin
delphinidin Delphinidin (also delphinidine) is an anthocyanidin, a primary plant pigment, and also an antioxidant. Delphinidin gives blue hues to flowers in the genera ''Viola'' and ''Delphinium''. It also gives the blue-red color of the grape variety Cab ...
needs six
hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
groups. To date, dahlias have only developed five, so the closest that breeders have come to achieving a "blue" specimen are variations of mauve, purples and lilac hues. By the beginning of the twentieth century, a number of different types were recognised. These terms were based on shape or colour, and the National Dahlia Society included cactus, pompon, single, show and fancy in its 1904 guide. Many national societies developed their own classification systems until 1962 when the International Horticultural Congress agreed to develop an internationally recognised system at its Brussels meeting that year, and subsequently in Maryland in 1966. This culminated in the 1969 publication of ''The International Register of Dahlia Names'' by the
Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...
which became the central registering authority. This system depended primarily on the visibility of the central disc, whether it was open-centred or whether only ray florets were apparent centrally (double bloom). The double-bloom cultivars were then subdivided according to the way in which they were folded along their longitudinal axis: flat, involute (curled inwards) or revolute (curling backwards). If the end of the ray floret was split, they were considered fimbriated. Based on these characteristics, nine groups were defined plus a tenth miscellaneous group for any cultivars not fitting the above characteristics. Fimbriated dahlias were added in 2004, and two further groups (Single and Double orchid) in 2007. The last group to be added, Peony, first appeared in 2012. In many cases the bloom diameter was then used to further label certain groups from miniature to giant. This practice was abandoned in 2012.


Modern system (RHS)

There are now more than 57,000 registered
cultivars A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue cult ...
, which are officially registered through the
Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...
(RHS). The official register is ''The International Register of Dahlia Names 1969'' (1995 reprint) which is updated by annual supplements. The original 1969 registry published about 14,000 cultivars adding a further 1700 by 1986 and in 2003 there were 18,000. Since then about a hundred new cultivars are added annually. ;Flower type The official RHS classification lists fourteen groups, grouped by flower type, together with the abbreviations used by the RHS; ;Flower size Earlier versions of the registry subdivided some groups by flower size. Groups 4, 5, 8 and 9 were divided into five subgroups (A to E) from Giant to Miniature, and Group 6 into two subgroups, Small and Miniature. Dahlias were then described by Group and Subgroup, e.g. 5(d) ‘Ace Summer Sunset’. Some Dahlia Societies have continued this practice, but this is neither official nor standardised. As of 2013 The RHS uses two size descriptors * Dwarf Bedder (Dw.B.) – not usually exceeding in height, e.g. 'Preston Park' (''Sin/DwB'') * Lilliput dahlias (Lil) – not usually exceeding in height, with single, semi-double or double florets up to in diameter. ("baby" or "top-mix" dahlias), e.g. 'Harvest Tiny Tot' (''Misc/Lil'') Sizes can range from tiny micro dahlias with flowers less than 50'' ''mm to giants that are over 250'' ''mm in diameter. The groupings listed here are from the New Zealand Society: * Giant-flowered cultivars have blooms with a diameter over 250 mm. * Large-flowered cultivars have blooms with a diameter of 200–250 mm. * Medium-flowered cultivars have blooms with a diameter of 155–350 mm. * Small-flowered cultivars have blooms with a diameter of 115–155 mm. * Miniature-flowered cultivars have blooms with a diameter of 50–115 mm. * Pompom-flowered cultivars have blooms with a diameter less than 50 mm. In addition to the official classification and the terminology used by various dahlia societies, individual horticulturalists use a wide range of other descriptions, such as 'Incurved' and abbreviations in their catalogues, such as CO for Collarette.


Branding

Some plant growers include their brand name in the cultivar name. Thus Fides (part of the Dümmen Orange Group) in the Netherlands developed a series of cultivars which they named the Dahlinova series, for example Dahlinova 'Carolina Burgundy'. These are Group 10 Miscellaneous in the RHS classification scheme.


Double dahlias

In 1805, several new species were reported with red, purple, lilac, and pale yellow coloring, and the first true double flower was produced in Belgium. One of the more popular concepts of dahlia history, and the basis for many different interpretations and confusion, is that all the original discoveries were single-flowered types, which, through hybridization and selective breeding, produced double forms. Many of the species of dahlias then, and now, have single-flowered blooms. ''D. coccinea'', the third dahlia to bloom in Europe, was a single. But two of the three drawings of dahlias by Dominguez, made in Mexico between 1570 and 1577, showed definite characteristics of doubling. In the early days of the dahlia in Europe, the word "double" simply designated flowers with more than one row of petals. The greatest effort was now directed to developing improved types of double dahlias. During the years 1805 to 1810 several people claimed to have produced a double dahlia. In 1805 Henry C. Andrews made a drawing of such a plant in the collection of Lady Holland, grown from seedlings sent that year from Madrid. Like other doubles of the time it did not resemble the doubles of today. The first modern double, or full double, appeared in Belgium; M. Donckelaar, Director of the Botanic Garden at
Louvain Leuven (, , ), also called Louvain (, , ), is the capital and largest city of the province of Flemish Brabant in the Flemish Region of Belgium. It is located about east of Brussels. The municipality itself comprises the sub-municipalities of ...
, selected plants for that characteristic, and within a few years secured three fully double forms. By 1826 double varieties were being grown almost exclusively, and there was very little interest in the single forms. Up to this time all the so-called double dahlias had been purple, or tinged with purple, and it was doubted if a variety untinged with that color was obtainable. In 1843, scented single forms of dahlias were first reported in Neu Verbass, Austria. ''D. crocea'', a fragrant variety grown from one of the Humboldt seeds, was probably interbred with the single ''D. coccinea''. A new scented species would not be introduced until the next century when the ''D. coronata'' was brought from Mexico to Germany in 1907. The exact date the dahlia was introduced in the United States is uncertain. One of the first dahlias in the USA may have been the ''D. coccinea speciosissima'' grown by William Leathe, of Cambridgeport, near Boston, around 1929. According to Edward Sayers, "it attracted much admiration, and at that time was considered a very elegant flower, it was however soon eclipsed by that splendid scarlet, the Countess of Liverpool". However, nine cultivars were already listed in the catalog from Thornburn, 1825. And even earlier reference can be found in a catalogue from the Linnaean Botanical Garden, New York, 1820, that includes one scarlet, one purple, and two double orange Dahlias for sale. Sayers stated that "No person has done more for the introduction and advancement of the culture of the Dahlia than George C. Thorburn, of New York, who yearly flowers many thousand plants at his place at Hallet's Cove, near Harlaem. The show there in the flowering season is a rich treat for the lovers of floriculture : for almost every variety can be seen growing in two large blocks or masses which lead from the road to the dwelling-house, and form a complete field of the Dahlia as a foreground to the house. Mr. T. Hogg, William Read, and many other well-known florists have also contributed much in the vicinity of New York, to the introduction of the Dahlia. Indeed so general has become the taste that almost every garden has its show of the Dahlia in the season." In Boston too there were many collections, a collection from the Messrs Hovey of Cambridgeport was also mentioned. In 1835 Thomas Bridgeman, published a list of 160 double dahlias in his "Florist's Guide". 60 of the choicest were supplied by Mr. G. C. Thornburn of Astoria, New York, who got most of them from contacts in the UK. Not a few of them had taken prizes "at the English and American exhibitions".


"Stars of the Devil"

In 1872 J. T. van der Berg of Utrecht in the Netherlands received a shipment of seeds and plants from a friend in Mexico. The entire shipment was badly rotted and appeared to be ruined, but van der Berg examined it carefully and found a small piece of root that seemed alive. He planted and carefully tended it; it grew into a plant that he identified as a dahlia. He made cuttings from the plant during the winter of 1872–1873. This was an entirely different type of flower, with rich, red color and a high degree of doubling. In 1874 van der Berg catalogued it for sale, calling it ''Dahlia juarezii'' to honor Mexican President Benito Pablo Juarez, who had died the year before, and described it as "...equal to the beautiful color of the red poppy. Its form is very outstanding and different in every respect of all known dahlia flowers." This plant has perhaps had a greater influence on the popularity of the modern dahlia than any other. Called "Les Etoiles du Diable" (Stars of the Devil) in France and "Cactus dahlia" elsewhere, the edges of its petals rolled backwards, rather than forward, and this new form revolutionized the dahlia world. It was thought to be a distinct mutation since no other plant that resembled it could be found in the wild. Today it is assumed that ''D. juarezii'' had, at one time, existed in Mexico and subsequently disappeared. Nurserymen in Europe crossbred this plant with dahlias discovered earlier; the results became the progenitors of all modern dahlia hybrids today.


Award of Garden Merit (RHS)

As of 2015, 124 dahlia cultivars have gained the
Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...
's
Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...
, including: * "Bednall beauty" * "
Bishop of Llandaff The Bishop of Llandaff is the Ordinary (officer), ordinary of the Church in Wales Diocese of Llandaff. Area of authority The diocese covers most of the County of Glamorgan. The bishop's cathedra, seat is in the Llandaff Cathedral, Cathedral Chu ...
" * "Clair de lune" * "David Howard" * "Ellen Huston" * "Fascination" * "Gallery Art Deco" * "Gallery Art Nouveau" * "Glorie van Heemstede" * "Honka" * " Moonfire" * "Twyning's After Eight"


Uses

The Aztecs used dahlias to treat
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
, and employed the long hollow stem of the ''D. imperialis'' for water pipes. Europeans attempted to introduce the tubers as a food crop, but this was unpopular. The dahlia is considered one of the native ingredients in Oaxacan cuisine; several cultivars are still grown especially for their large, sweet potato-like tubers. Dacopa, an intense mocha-tasting extract from the roasted tubers, is used to flavor beverages throughout
Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...
.


Medicine

In Europe and America, prior to the discovery of
insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (''INS)'' gene. It is the main Anabolism, anabolic hormone of the body. It regulates the metabol ...
in 1923, diabetics—as well as consumptives—were often given a substance called ''Atlantic starch'' or ''diabetic sugar'', derived from
inulin Inulins are a group of naturally occurring polysaccharides produced by many types of plants, industrially most often extracted from chicory. The inulins belong to a class of dietary fibers known as fructans. Inulin is used by some plants as a ...
, a naturally occurring form of
fruit sugar Fructose (), or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorb ...
, extracted from dahlia tubers. Inulin is still used in clinical tests for kidney functionality.


In culture

Founded in 1936, the Bloemencorso Zundert is the largest
flower parade A flower parade is a parade in which the floats, vehicles, boats, participants, animals and other things are decorated or covered in flowers. Often there are other elements like marching bands and people in costumes. Flower parades are held in ...
in the world entirely made by volunteers using the dahlia. The parade takes place on the first Sunday of September in
Zundert Zundert () is a Municipalities of the Netherlands, municipality and town in the south of the Netherlands bordering Belgium, in the province of North Brabant. Zundert is the birthplace of Post-Impressionism, Post-Impressionist painter Vincent va ...
, Netherlands. The floats are large artworks made of steel wire, cardboard,
papier-mâché file:JacmelMardiGras.jpg, upright=1.3, Mardi Gras papier-mâché masks, Haiti Papier-mâché ( , , - the French term "mâché" here means "crushed and ground") is a versatile craft technique with roots in ancient China, in which waste paper is s ...
and flowers. In the Bloemencorso Zundert, mostly dahlias are used to decorate the objects and it takes thousands of them just to cover one float. Around 8 million dahlias are needed for the entire corso. Of these, around 6 million are cultivated in Zundert. The dahlia was declared the
national flower In a number of countries, plants have been chosen as symbols to represent specific geographic areas. Some countries have a country-wide floral emblem; others in addition have symbols representing subdivisions. Different processes have been used t ...
of
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
in 1963.


See also

* List of dahlia diseases * Dahlia symbolism *
Dahlia Hill Dahlia Hill (DH) is both a protected garden area in the Lower Peninsula of Michigan, encompassing of terraced gardens, and the a 501(c) organization#501(c)(3), 501(c)(3) non-profit educational organization that runs the garden. Located in the c ...


References


Bibliography

* * * * * * * *


Articles

* * Sherff, Earl Edward, 1951: Epiphytum, a new section of the genus Dahlia Cav. Bot Leaflets: 4,21 *
Saar, Dayle Ellyn. A phylogenetic analysis of the genius Dahlia (asteraceae): An interdisciplinary study. Ph D Thesis, Northern Illinois University, 1999
* *


Societies

* *
Dahlia
* *

* *


External links

* * *


The United Kingdom National Dahlia Collection

North American Dahlia Shows

Dahlia
Flower Care
Dahlia Pinnata Eatable Plans

Info about care for dahlias
*
''Dahlia rosea'' at pfaf
*
''Dahlia pinnata'' at pfaf

Gallery of Dahlia Images

Hans V. Hansen. Native (wild) Dahlias – taxonomy, historical review, and the derivation of cultivars, in Trial of Dahlia 2008, Final Report. Royal Horticultural Society



Databases


Global Compositae Database
{{Authority control Asteraceae genera Crops originating from Mexico Oaxacan cuisine Garden plants of North America National symbols of Mexico Perennial plants Flora of Mexico Flora of Southern America Plants used in Native American cuisine Crops originating from indigenous Americans Taxa named by Antonio José Cavanilles