Sunflower (genus)

sunflowers
	Sunflowers ( Helianthus annuus )
Systematics
	Euasterids II
Order :	Astern-like (Asterales)
Family :	Daisy family (Asteraceae)
Subfamily :	Asteroideae
Tribe :	Heliantheae
Genre :	sunflowers
Scientific name
	Helianthus
	L.

The sunflower ( Helianthus ) form a plant genus in the subfamily of Asteroideae within the family of the daisy family (Asteraceae). All about 67 species are common in North America .

Two species are important as cultivated plants in Central Europe : the actual sunflower ( Helianthus annuus ) and Jerusalem artichoke ( Helianthus tuberosus ).

description

Illustration of Helianthus debilis

Detail of Helianthus petiolaris

Jerusalem artichoke flower head ( Helianthus tuberosus )

Vegetative characteristics

The Helianthus species are annual or perennial herbaceous plants and usually reach heights of 20 to 300 (5 to 500) centimeters. Few species form rhizome tubers as persistence organs. The independently upright or ascending to prostrate or lying stems are often branched in the upper part.

The leaves, which are only basal or distributed over the entire stem, are opposite and / or alternate , are stalked or sessile. The simple leaf blade is usually three- nerved , only with Helianthus eggertii , Helianthus smithii and Helianthus maximilliani also single-nerved. Usually the leaf blade is triangular, lanceolate-linear, lanceolate-egg-shaped, linear or egg-shaped in outline. The base of the blades is heart-shaped or narrow-wedge-shaped. The leaf margin is usually entire or toothed, rarely lobed. The leaf surfaces can be hairless or hairy; they are often dotted with glands.

Inflorescences and flowers

The flower heads stand together individually or in more or less clusters of corymbs, corymbs or spikes . In the cup-shaped inflorescence there are both tubular and ray flowers. The involucre (= involucre) (chalice is misleading here, because it is not a part of the flower, so do not calyx , but a part of the inflorescence) is more or less hemispherical, sometimes bell-shaped or cylindrical. It has a diameter of 5 to 40 millimeters or more, with varieties more than 200 millimeters can be achieved. The per involucre 11-40 (or more than 100 at Varieties) durable bracts are arranged in two, three or more rows. The bracts resemble each other or are designed differently. The flower head base is flat to slightly convex, only in Helianthus porteri it is conical. It is covered with chaff leaves , which are more or less folded lengthways rectangular-elongated and have three teeth or are occasionally entire; sometimes their tips are reddish or purple in color.

The flower baskets contain a row with 5 to 30 or more (or more than 100 in the case of cultivars) ray-flowers (= ray-flowers), rarely missing. The zygomorphic ray florets are sterile and their tubular, fused petals are mostly yellow. The number of tubular flowers (= disc flowers) is between (15) 30 and more than 150, in the case of cultivars also over 1000. The radially symmetrical tubular flowers are hermaphroditic, fertile and their petals are yellow or at least reddish in color at the tip. The crown tube is shorter than the bell-shaped crown throat and ends in five triangular crown lobes. The ramifications of the stylus are slender, the appendages are more or less pointed.

Infructescence and fruits

The achenes are mostly purple-black, sometimes spotted, more or less inverted pyramidal and ± flattened. In Helianthus porteri there is no pappus , in other species the pappi fall off easily. Usually they consist of 2 or 3 lanceolate, awny or irregularly serrated bristles that are 1 to 5 millimeters long. There are also up to eight shorter scales with a length of 0.2 to 2 millimeters.

Sets of chromosomes

The basic chromosome number is x = 17.

Systematics

Helianthus debilis

Helianthus decapetalus

Example of a species with a branched inflorescence: Helianthus giganteus

Helianthus maximiliani

Helianthus microcephalus

Helianthus mollis

Helianthus petiolaris

Helianthus porteri

Willow-leaved sunflower ( Helianthus salicifolius )

Helianthus schweinitzii

Upper part of Jerusalem artichoke ( Helianthus tuberosus )

In the genus sunflowers ( Helianthus ) there are (52 to) about 67 species. Here are the species according to Edward E. Schilling in the Flora of North America :

Helianthus agrestis Pollard : It occurs in the US states of Florida and Georgia .
Helianthus angustifolius L .: It is widespread in the United States.
Sunflower ( Helianthus annuus L. ): It is widespread from Canada to the United States to Mexico. It is cultivated in many varieties. It is a neophyte in many areas of the world .
Helianthus argophyllus Torr. & A.Gray : It is found in the US states of Texas , Florida and North Carolina .
Helianthus arizonensis R.C. Jacks. : It occurs in the US states of Arizona and New Mexico.
Helianthus atrorubens L .: It is widespread in the eastern and southeastern United States.
Helianthus bolanderi A.Gray : It occurs in the US states of Oregon and California .
Helianthus californicus DC. : It occurs from the US state California to the Mexican state Baja California.
Helianthus carnosus Small : This endemic occurs only in Florida.
Helianthus ciliaris DC. : It iswidespreadin the United States and Mexico .
Helianthus cusickii A.Gray : It occurs in the US states of Oregon, Washington , Idaho , Nevada and California.
Helianthus debilis Nutt. : There are about five subspecies:
- Helianthus debilis subsp. cucumerifolius (Torrey & A.Gray) Heiser (Syn .: Helianthus cucumerifolius Torr. & A.Gray ): It occurs in the eastern and southern United States.
- Helianthus debilis Nutt. subsp. debilis Heiser : It only thrives in Florida at altitudes of 0 to 10 meters.
- Helianthus debilis subsp. silvestris Heiser : It thrives at altitudes of 10 to 100, sometimes more, meters only in Texas.
- Helianthus debilis subsp. tardiflorus Heiser : It thrives on sandy beaches at altitudes of 0 to 100, sometimes more, meters in the US states of Alabama, Florida, Georgia and Mississippi .
- Helianthus debilis subsp. vestitus (E. Watson) Heiser : It only thrives at altitudes of 0 to 10 meters in Florida and is endangered.
Helianthus decapetalus L .: It is widespread in Canada and the United States.
Helianthus deserticola Heiser : It thrives in dry, open locations at altitudes of 400 to 1500 meters in the US states of Arizona, Nevada and Utah.
Helianthus divaricatus L .: It is widespread in Canada and the United States.
Helianthus eggertii Small : It occurs in the US states of Alabama , Kentucky and Tennessee .
Helianthus exilis A.Gray : It thrives at altitudes of 100 to 1400 meters only in the US state of California and is endangered.
Helianthus floridanus A. Gray ex Chapman : It occurs in the US states of Alabama, Florida, Georgia , Louisiana , South Carolina and North Carolina .
Helianthus giganteus L .: It is widespread in Canada and the United States.
Helianthus glaucophyllus D.M.Smith : It occurs in the US states in Tennessee, North Carolina and South Carolina.
Helianthus gracilentus A.Gray : It occurs in California and Baja California, Mexico.
Helianthus grosseserratus M. Martens : It is widespread in Canada and the United States.
Helianthus heterophyllus Nutt. : It occurs in the southern and southeastern United States.
Helianthus hirsutus Raf. : It iswidespreadin the United States, Ontario, and Mexico.
Helianthus laciniatus A.Gray : It occurs in the US states of Texas, New Mexico and Mexico.
Helianthus laevigatus Torrey & A.Gray : It is found in the US states of South Carolina, North Carolina, Virginia and West Virginia .
Helianthus longifolius Pursh : It occurs in the US states of Alabama, Georgia and North Carolina.
Helianthus maximiliani Schrader : It is widespread in Canada, the United States, and Mexico.
Helianthus microcephalus Torrey & A.Gray : It is found in the United States.
Helianthus mollis Lam. : It occurs in Ontario, Canada and in the United States.
Helianthus neglectus Heiser : It occurs in the US states of Texas and New Mexico.
Helianthus niveus (Benth.) Brandegee : There are two subspecies:
- Helianthus niveus (Benth.) Brandegee subsp. niveus : It occurs in the southwestern United States and Mexico.
- Helianthus niveus subsp. tephrodes (A.Gray) Heiser : It thrives at altitudes of 50 to 300 meters in the US states of Arizona as well as California and the Mexican state of Sonora .
Helianthus nuttallii Torrey & A.Gray : It is widespread in three subspecies in Canada and the United States.
- Helianthus nuttallii Torrey & A. Gray subsp. nuttallii (Syn .: Helianthus nuttallii subsp. canadensis R.W. Long )
- Helianthus nuttallii subsp. parishii (A.Gray) Hoarse : Endangered and only found in California.
- Helianthus nuttallii subsp. rydbergii (Britton) RWLong
Helianthus occidentalis Riddell : There are two subspecies:
- Helianthus occidentalis Riddell subsp. occidentalis : It is common in the United States.
- Helianthus occidentalis subsp. plantagineus (Torrey & A.Gray) Heiser : It thrives in dry, open locations at altitudes of 10 to 100, sometimes more, meters in the US states of Arkansas and Texas.
Helianthus paradoxus Heiser : It occurs in the US states of Texas and New Mexico.
Helianthus pauciflorus Nutt. : It occurs in two subspecies in Canada and the United States:
- Helianthus pauciflorus Nutt. subsp. subrhomboideus
- Helianthus pauciflorus subsp. subrhomboideus (Rydberg) O.Spring & EESchilling (Syn .: Helianthus subrhomboideus Rydberg , Helianthus laetiflorus var. subrhomboideus (Rydberg) Fernald , Helianthus pauciflorus var. subrhomboideus (Rydberg) Cronquist , Helianthus rigidus subsp. subrhomboideus (Rydberg) Heiser , Helianthus rigidus var . subrhomboideus (Rydberg) Cronquist ): This new combination took place in 1990.
Helianthus petiolaris Nutt. : It occurs in two subspecies in Canada and the United States.
- Helianthus petiolaris subsp. fallax hoarse
- Helianthus petiolaris Nutt. subsp. petiolaris
Helianthus porteri (A.Gray) Pruski : It occurs in the US states of Alabama, Georgia, North Carolina and South Carolina.
Helianthus praecox Engelmann & A.Gray : The three subspecies are only found in Texas:
- Helianthus praecox subsp. hirtus (Heiser) Heiser : This endemic is only known from one site near Carrizo Springs.
- Helianthus praecox Engelmann & A. Gray subsp. praecox
- Helianthus praecox subsp. runyonii (hoarse) hoarse
Helianthus praetermissus E. Watson : It is only known from one specimen collected in Cibola County, western New Mexico, in 1851. It has not been found since then and is therefore considered extinct.
Helianthus pumilus Nutt. : It occurs in the US states Colorado and Wyoming .
Helianthus radula (Pursh) Torrey & A.Gray : It is found in the US states of Alabama, Florida, Georgia, Louisiana, Mississippi and South Carolina.
Helianthus resinosus Small : It occurs in the US states of Alabama, Georgia, Florida, Mississippi, North Carolina and South Carolina.
Willow-leaved sunflower ( Helianthus salicifolius A. Dietrich ): It thrives at altitudes of 10 to 300 meters in the US states of Kansas , Montana , Nebraska , Oklahoma and Texas. It is cultivated and wild in some areas.
Helianthus schweinitzii Torrey & A.Gray : It is only found in the US states of North Carolina and South Carolina.
Helianthus silphioides Nutt. : It occurs in the US states of Alabama, Arkansas , Illinois , Kentucky , Louisiana, Mississippi, Missouri , Oklahoma and Tennessee.
Helianthus simulans E. Watson : It occurs in the US states Alabama, Florida, Georgia, Louisiana and South Carolina.
Helianthus smithii Heiser : It occurs in the US states of Alabama, Georgia and Tennessee.
Helianthus strumosus L .: It is widespread in Canada and the United States.
Jerusalem artichoke ( Helianthus tuberosus L. ): It is widespread in Canada and the United States. It is cultivated and is a neophyte in many areas of the world .
Helianthus verticillatus Small : It occurs in the US states of Alabama, Georgia and Tennessee.

There are some natural hybrids:

Helianthus × ambiguus (Torr. & A.Gray) Britton = Helianthus giganteus × Helianthus divaricatus
Helianthus × anomalus S.F.Blake = Helianthus annuus × Helianthus petiolaris : It occurs in the US states of Arizona and Utah .
Helianthus × cinereus (Torr. & A. Gray) RCJacks. & Guard = Helianthus mollis × Helianthus occidentalis
Helianthus × deserticola Heiser , developed from Helianthus annuus × Helianthus petiolaris : It occurs in the US states of Arizona, Nevada and Utah.
Helianthus × divariserratus R.W. Long = Helianthus grosseserratus × Helianthus divaricatus
Helianthus × doronicoides (Lam.) RCJacks. = Helianthus giganteus × Helianthus mollis
Helianthus × intermedius R.W. Long = Helianthus grosseserratus × Helianthus maximiliani : It occurs in Wisconsin .
Helianthus × kellermanii (Britton) RWLong = Helianthus grosseserratus × Helianthus salicifolius
Helianthus × laetiflorus Pers. = Helianthus pauciflorus × Helianthus tuberosus : It is widespread in Canada and the United States and is a neophyte in Europe, Argentina and New Zealand.
Helianthus × luxurians E. Watson = Helianthus giganteus × Helianthus grosseserratus
Helianthus × orgyaloides Cockerell = Helianthus maximiliani × Helianthus salicifolius : It occurs in the US state of Colorado .
Helianthus × multiflorus L. = Helianthus annuus × Helianthus decapetalus

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az ^ba ^bb ^bc ^bd ^be ^bf ^bg ^bh ^bi ^bj ^bk ^bl ^bm ^bn ^bo ^bp ^bq ^br ^bs ^bt ^bu ^bv ^bw ^bx Edward E. Schilling: Helianthus Linnaeus. , Pp. 141-166 - same text online as -printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico , Volume 21 - Magnoliophyta: Asteridae (in part): Asteraceae, part 3 , Oxford University Press, New York and Oxford, 2006, ISBN 0-19-530565-5 .
^ New Mexico Rare Plant Technical Council .
↑ ^a ^b ^c ^d ^e Helianthus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved March 3, 2018.

Web links

Commons : Sunflowers ( Helianthus ) - Collection of images, videos and audio files

[FoNA-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az ^ba ^bb ^bc ^bd ^be ^bf ^bg ^bh ^bi ^bj ^bk ^bl ^bm ^bn ^bo ^bp ^bq ^br ^bs ^bt ^bu ^bv ^bw ^bx Edward E. Schilling: Helianthus Linnaeus. , Pp. 141-166 - same text online as -printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico , Volume 21 - Magnoliophyta: Asteridae (in part): Asteraceae, part 3 , Oxford University Press, New York and Oxford, 2006, ISBN 0-19-530565-5 .

[HelianthusPraetermissus-2] New Mexico Rare Plant Technical Council .

[GRIN-3] Helianthus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved March 3, 2018.