''Helianthus decapetalus'', known by the common names thinleaf sunflower and thin-leaved sunflower, is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

. It is

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

to the Eastern and Central United States and

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, from

New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...

west to

Iowa Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

, and

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

, south as far as

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

and

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

. USDA, NRCS. 2014. The PLANTS Database (http://plants.usda.gov). National Plant Data Team, Greensboro, NC 27401-4901 USA. It produces yellow composite flowers in late summer or early fall. The name ''decapetalus'' means "with ten petals", referring to the 8-12

ray florets The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

on the

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

, resembling petals.

Description

The smooth slender stem of ''H. decapetalus'' is 60 to 200 cm (2 to 7 ft) tall and branched near the top. The ovate or lanceolate leaves are borne on 2- to 5-cm-long petioles and have serrated edges. They are 7 to 21 cm long and 4 to 10 cm wide. It has three to 10 flowerheads; each flowerhead is composed of 21 to 50

disk floret The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae we ...

s, and eight to 12

ray floret The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

s, which are 2.0 to 2.5 cm long. The bracts are typically 11 to 16 mm long, surpassing the flower disk by at least half their length. The fruit are 3.5- to 5.0-mm-long

cypselae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

with a pappus of two scales.

Distribution and habitat

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

, it grows in habitats such as floodplain forests and riverbanks. Its native habitats include woodland and forest edges. The presence of this species is dependent on appropriate

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

, and it may be eliminated from an area by development, changes in land use, or competition with

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

Ecology

The flowers attract many kinds of insects, including bees and butterflies, some of which, such as the

painted lady ''Vanessa cardui'' is the most widespread of all butterfly species. It is commonly called the painted lady, or formerly in North America the cosmopolitan. Description File:Vanessa cardui MHNT CUT 2013 3 14 Pontfaverger-Moronvilliers Dos. ...

and the

silvery checkerspot ''Chlosyne nycteis'', the silvery checkerspot, is a species of Nymphalinae butterfly that occurs in North America. It is listed as a species of special concern in Connecticut and Maine, and is believed extirpated in Connecticut, Massachusetts, ...

Muskrat The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitat ...

s eat the leaves and stems and use the stems in the construction of their lodges.

References

External links

{{Taxonbar, from=Q9353368 decapetalus Flora of North America Plants described in 1753 Taxa named by Carl Linnaeus