Helianthus
| Sunflowers | |
|---|---|
 | |
Common sunflower | |
Scientific classification  | |
| Kingdom: | Plantae |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Subfamily: | Asteroideae |
| Supertribe: | Helianthodae |
| Tribe: | Heliantheae |
| Genus: | Helianthus L.[1] |
Synonyms[1] | |
Harpalium (Cass.) Cass. | |
Helianthus or sunflower (/ˌhiːliˈænθəs/)[2] is a genus of plants comprising about 70 species.[3][4] Except for three species in South America, all Helianthus species are native to North America. The common name, "sunflower", typically refers to the popular annual species Helianthus annuus, or the common sunflower, whose round flower heads in combination with the ligules look like the sun.[5] This and other species, notably Jerusalem artichoke (H. tuberosus), are cultivated in temperate regions and some tropical regions as food crops for humans, cattle, and poultry, and as ornamental plants.[6]
Perennial sunflower species are not as common in garden use due to their tendency to spread rapidly and become invasive. The whorled sunflower, H. verticillatus, was listed as an endangered species in 2014 when the U.S. Fish and Wildlife Service issued a final rule protecting it under the Endangered Species Act. The primary threats are industrial forestry and pine plantations in Alabama, Georgia, and Tennessee. They grow to 1.8 m (6 ft) and are primarily found in woodlands, adjacent to creeks and moist, prairie-like areas.[7]
Contents
1 Description
2 Production
2.1 Fertilizer Use
2.2 Production in Brazil
3 Diversity
4 Gallery
5 Growth Stages
6 References
7 External links
8 See also
Description
Close-up of a sunflower
The disk of a sunflower is made up of many little flowers. The ray flowers here are dried up.
A field of sunflowers in North Carolina
Sunflowers are usually tall annual or perennial plants that in some species can grow to a height of 300 cm (120 in) or more. They bear one or more wide, terminal capitula (flower heads), with bright yellow ray florets at the outside and yellow or maroon (also known as a brown/red) disc florets inside. Several ornamental cultivars of H. annuus have red-colored ray florets; all of them stem from a single original mutant.[8] During growth, sunflowers tilt during the day to face the sun but stop once they begin blooming. This tracking of the sun in young sunflower heads is called heliotropism. By the time they are mature, sunflowers generally face east.[9] The rough and hairy stem is branched in the upper part in wild plants but is usually unbranched in domesticated cultivars. The petiolate leaves are dentate and often sticky. The lower leaves are opposite, ovate, or often heart-shaped.
They are distinguished technically by the fact that the ray florets (when present) are sterile, and by the presence on the disk flowers of a pappus that is of two awn-like scales that are caducous (that is, easily detached and falling at maturity). Some species also have additional shorter scales in the pappus, and one species lacks a pappus entirely. Another technical feature that distinguishes the genus more reliably, but requires a microscope to see, is the presence of a prominent, multicellular appendage at the apex of the style.
Quite a bit of variability is seen among the perennial species that make up the bulk of those in the genus. Some have most or all of the large leaves in a rosette at the base of the plant and produce a flowering stem that has leaves that are reduced in size. Most of the perennials have disk flowers that are entirely yellow, but a few have disk flowers with reddish lobes. One species, H. radula, lacks ray flowers altogether.
Helianthus species are used as food plants by the larvae of many lepidopterans. The seeds of H. annuus are used as human food.
Production
Fertilizer Use
The Journal of Environmental Management has analyzed the impact of various nitrogen-based fertilizers on the growth of sunflowers. In the Province of Siena (Italy), farmers attempted to reduce dependence on petroleum by using different forms of nitrogen fertilizer to better manage the fertilizers’ influence on sunflower growth. Ammonium nitrate was found to produce better nitrogen absorption than urea, which performed better in low-temperature areas.[10]
Production in Brazil
In Brazil, a unique system of production called the soybean-sunflower system is used: sunflowers are planted first, and then soybean crops follow, reducing idle periods and increasing total sunflower production and profitability. Sunflowers are usually planted in the extreme southern or northern regions of the country. Frequently, in the southern regions, sunflowers are grown in the beginning of rainy seasons, and soybeans can then be planted in the summer.[11] Researchers have concluded that the soybean-sunflower method of plantation could be further improved through changes in fertilizer use. The current method has been shown to have positive environmental impacts.[12]
Ukraine and Russia were top sunflower producers of the world in 2017. They contributed half of the sunflower seed production globally, which is approximately 23 MMT altogether.[13]
| Contries | Million metric tonns |
|---|---|
Ukraine | 11.9 |
Russia | 10.89 |
European Union | 8.57 |
Argentina | 3.4 |
Turkey | 1.32 |
| Other | 8.45 |
| Source: www.statistica.com [14] | |
Diversity
- Accepted species[15][16]
Helianthus agrestis Pollard – southeastern sunflower – Florida Georgia
Helianthus ambiguus Britt. – Wisconsin Michigan Ohio New York State
Helianthus angustifolius L. – swamp sunflower – Texas + Florida north to southern Illinois + Long Island
Helianthus annuus L. – common sunflower, girasol – most of United States + Canada
Helianthus anomalus S.F.Blake – western sunflower – Nevada Utah Arizona New Mexico
Helianthus argophyllus Torr. & A.Gray – silverleaf sunflower – Texas North Carolina Florida
Helianthus arizonensis R.C.Jacks. – Arizona sunflower – Arizona New Mexico
Helianthus atrorubens L. – purpledisk sunflower – Louisiana Alabama Georgia Florida South Carolina North Carolina Tennessee Kentucky Virginia
Helianthus bolanderi A.Gray – serpentine sunflower – California Oregon
Helianthus × brevifolius E.Watson – Texas Indiana Ohio
Helianthus californicus DC. – California sunflower – California
Helianthus carnosus Small – lakeside sunflower – Florida
Helianthus ciliaris DC. – Texas blueweed – Washington California Arizona New Mexico Nevada Utah Texas Oklahoma Colorado Kansas Illinois Tamaulipas Coahuila Chihuahua Sonora
Helianthus cinereus Small – Missouri Kentucky Indiana Ohio
Helianthus coloradensis Cockerell – prairie sunflower – Colorado New Mexico
Helianthus cusickii A.Gray – Cusick's sunflower – Washington Oregon California Idaho Nevada
Helianthus debilis Nutt. – cucumberleaf Sunflower – Texas to Maine; Mississippi
Helianthus decapetalus L. – thinleaf sunflower – eastern United States; Ontario Quebec
Helianthus deserticola Heiser – desert sunflower – Arizona Nevada Utah
- †Helianthus diffusus Sims – Missouri†
Helianthus dissectifolius R.C.Jacks. – Mexico
Helianthus divaricatus L. – woodland sunflower or rough woodland sunflower – eastern United States; Ontario Quebec
Helianthus × divariserratus R.W.Long Michigan Indiana Ohio Connecticut
Helianthus × doronicoides Lam. – Texas Oklahoma Arkansas Missouri Iowa Minnesota Illinois Kentucky Indiana Ohio Pennsylvania Michigan New Jersey Virginia
Helianthus eggertii Small – Alabama, Kentucky, and Tennessee
Helianthus exilis A.Gray – California
Helianthus floridanus A.Gray ex Chapm. – Florida sunflower – Louisiana Alabama Georgia Florida South Carolina North Carolina
Helianthus giganteus L. – giant sunflower – eastern United States; most of Canada
Helianthus glaucophyllus D.M.Sm – whiteleaf sunflower – Tennessee South Carolina North Carolina
Helianthus × glaucus Small – scattered locales in southeastern United States
Helianthus gracilentus A.Gray – slender sunflower – California
Helianthus grosseserratus M.Martens – sawtooth sunflower – Great Plains, Great Lakes, Ontario Quebec
Helianthus heterophyllus Nutt. – variableleaf sunflower – Coastal Plain Texas to North Carolina
Helianthus hirsutus Raf. – hairy sunflower – central + Eastern United States, Ontario
Helianthus × intermedius R.W.Long – intermediate sunflower – scattered locales in United States
Helianthus laciniatus A.Gray – alkali sunflower – Arizona New Mexico Texas Coahuila Nuevo León
Helianthus × laetiflorus Pers. – cheerful sunflower, mountain sunflower – scattered in eastern + central United States + Canada
Helianthus laevigatus Torr. & A.Gray – smooth sunflower – Georgia South Carolina North Carolina Virginia Maryland West Virginia
Helianthus lenticularis Douglas ex Lindl. California Texas
Helianthus longifolius Pursh – longleaf sunflower – Alabama Georgia North Carolina
Helianthus × luxurians (E.Watson) E.Watson – Great Lakes region
Helianthus maximiliani Schrad. – Maximillian sunflower – much of United States + Canada
Helianthus membranifolius Poir. – French Guiana
Helianthus mollis Lam. – downy sunflower, ashy sunflower – Ontario, eastern + central United States
Helianthus multiflorus L. – manyflower sunflower – Ohio
Helianthus navarri Phil. – Chile
Helianthus neglectus Heiser – neglected sunflower – New Mexico Texas
Helianthus niveus (Benth.) Brandegee – showy sunflower – California Arizona; Baja California, Baja California Sur
Helianthus nuttallii Torr. & A.Gray – western + central United States + Canada
Helianthus occidentalis Riddell – fewleaf sunflower, western sunflower – Great Lakes region, scattered in southeastern United States
Helianthus × orgyaloides Cockerell – Colorado Kansas
Helianthus paradoxus Heiser – paradox sunflower – Utah New Mexico Texas
Helianthus pauciflorus Nutt. – stiff sunflower – central United States + Canada
Helianthus petiolaris Nutt. – prairie sunflower, lesser sunflower – much of United States + Canada
Helianthus porteri (A.Gray) Pruski – Porter's sunflower – Alabama Georgia South Carolina North Carolina
Helianthus praecox Engelm. & A.Gray Texas sunflower – Texas
- †Helianthus praetermissus – New Mexico sunflower – New Mexico†
Helianthus pumilus Nutt. – little sunflower – Colorado Wyoming Montana Utah Idaho
Helianthus radula (Pursh) Torr. & A.Gray – rayless sunflower – Louisiana Mississippi Alabama Georgia South Carolina Florida
Helianthus resinosus Small – rescindot sunflower – Mississippi Alabama Georgia South Carolina North Carolina Florida
Helianthus salicifolius A.Dietr. – willowleaf sunflower – Texas Oklahoma Kansas Missouri Illinois Wisconsin Ohio Pennsylvania New York State
Helianthus sarmentosus Rich. – French Guiana
Helianthus scaberrimus Elliott – South Carolina
Helianthus schweinitzii Torr. & A.Gray – Schweinitz's sunflower – South Carolina North Carolina
Helianthus silphioides Nutt. – rosinweed sunflower – Lower Mississippi Valley
Helianthus simulans E.Watson – muck sunflower – southeastern United States
Helianthus smithii Heiser – Smith's sunflower – Alabama Georgia Tennessee
Helianthus speciosus Hook. – Michoacán
Helianthus strumosus L. – eastern + central United States + Canada
Helianthus subcanescens (A.Gray) E.Watson – Manitoba, north-central United States
Helianthus subtuberosus Bourg.
Helianthus tuberosus L. – Jerusalem artichoke, sunchoke, earth-apple, topinambur – much of United States + Canada
Helianthus verticillatus Small – whorled sunflower – Alabama Georgia Tennessee
- Formerly included[15]
Flourensia thurifera (Molina) DC. (as H. thurifer Molina)
Helianthella quinquenervis (Hook.) A.Gray (as H. quinquenervis Hook.)
Helianthella uniflora var. uniflora (as H. uniflorus Nutt.)
Pappobolus imbaburensis (Hieron.) Panero (as H. imbaburensis Hieron.)
Viguiera procumbens (Pers.) S.F.Blake (as H. procumbens Pers.)
Gallery
Helianthus decapetalus
"Plenus"
Sunflower leaf structure
Prairie sunflower
(H. petiolaris)
Giant sunflower
(H. giganteus)
Red sunflower
Helianthus
'Strawberry Blonde'
Willowleaf sunflower
(H. salicifolius)
Sunflower bud
Jerusalem artichoke
(H. tuberosus)
Leaves of sunflower plant
Rear view of sunflower head
H. annuus
H. laetiflorus
Growth Stages
The growth of a sunflower strictly depends on its genetic makeup and background.[17] Additionally, the season it is planted will have effects on its development. Sunflower development is classified by a series of vegetative stages and reproductive stages that can be determined by identifying the heads or main branch of a single head or branched head Some diseases cause discoloration; therefore, it is important to use disease-free heads to best determine plant development.[17]
References
^ ab "Helianthus". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA). Retrieved 2011-02-22..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"""""""'""'"}.mw-parser-output .citation .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ Sunset Western Garden Book. Leisure Arts. 1995. pg. 606–607.
^ Schilling, Edward E. (2006). "Helianthus". In Flora of North America Editorial Committee. Flora of North America North of Mexico (FNA). 21. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
^ "Sunflower Production". North Dakota State University. Archived from the original on August 18, 2016. Retrieved July 12, 2016.
^ Shorter Oxford English Dictionary, 6th ed. United Kingdom: Oxford University Press. 2007. p. 3804. ISBN 978-0-19-920687-2.
^ RHS A-Z Encyclopedia of Garden Plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 978-1-4053-3296-5.
^ Remillard, Ashley (August 4, 2014) "U.S. Fish and Wildlife Service Issues Final Rule Protecting Three Flowers" Archived 2014-08-12 at the Wayback Machine Endangered Species Law and Policy Blog, Nossaman LLP
^ Heiser, C.B. The Sunflower. University of Oklahoma Press. 1981.
^ "How Does a Sunflower Move?". Home Guides – SF Gate. Archived from the original on 2014-10-18.
^ Spinelli, D; Bardi, L; Fierro, A; Jez, S; Basosi, R (2017). "Environmental analysis of sunflower production with different forms of mineral nitrogen fertilizers". The International Journal of Life Cycle Assessment. Journal of Environmental Management. 22 (4): 492–501. doi:10.1007/s11367-016-1089-6.
^ Castro, C; Leite, Regina. "Main aspects of sunflower production in Brazil". proquest. Retrieved Feb 7, 2019.
^ Mastuura, MISF; Dias, FRT; Picoli, JF; Lucas, KRG; Castro, C; Hirakuri, MH (2017). "Life-cycle assessment of the soybean-sunflower production system in the Brazilian Cerrado". The International Journal of Life Cycle Assessment. 22 (4): 492–501. doi:10.1007/s11367-016-1089-6.
^ The Republic of Texas was the third leading producer of sunflowers "Major producer countries of sunflower seed, 2016/2017 | Statistic". Statista. Retrieved 2018-08-10.
^ "Major producer countries of sunflower seed, 2016/2017 | Statistic". Statista. Retrieved 2018-08-10.
^ ab "Helianthus". The Plant List. Missouri Botanical Garden. Royal Botanic Gardens, Kew.
^ "Helianthus". County-level distribution maps from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.
^ ab Berglund, Duane. "Sunflower Production". ag,ndsu. NDSU Extension Service and N.D. Agricultural Experiment Station. Retrieved Feb 7, 2019.
External links
 | Wikimedia Commons has media related to Helianthus. |
 | Wikispecies has information related to Helianthus |
See also
spiral in the sunflower- Fermat's spiral
- Phyllotaxis
- Stegocintractia junci
