Symphyotrichum Dumosum

''Symphyotrichum dumosum'' (formerly ''Aster dumosus'') is a species of flowering plant of the family Asteraceae commonly known as rice button aster and bushy aster. It is native to much of eastern and central North America, as well as Haiti and Dominican Republic. It is a perennial, herbaceous plant that may reach a height of .

Description

''Symphyotrichum dumosum'' is a perennial, herbaceous plant that grows up to high.

Flowers

''Symphyotrichum dumosum'' is a late-summer and fall blooming perennial, with flower heads opening August–October. The flower heads are about diameter when in bloom and grow in open and much-branched paniculiform arrays. Each has many tiny florets put together into what appear as one.

Involucres and phyllaries

On the outside the flower heads of all members of the family Asteraceae are small bracts that look like scales. These are called '' phyllaries'', and together they form the involucre that protects the individual flowers in the head before they open. The involucres of ''Symphyotrichum dumosum'' are cylinder-bell in shape and usually long.

The phyllaries are appressed or slightly spreading. The shape of the outer phyllaries is oblong-oblanceolate or linear-oblanceolate, and the innermost phyllaries are linear. They are in strongly unequal rows, meaning they are very staggered and do not end at the same point, and they are hairless.

Florets

The 15–33 ray florets are blue, pink, purple, or white, with a length averaging and width of . Ray florets in the ''Symphyotrichum'' genus are exclusively female, each having a pistil (with style, stigma, and ovary) but no stamen; thus, ray florets accept pollen and each can develop a seed, but they produce no pollen.

The 15–30 disk florets start out as pale yellow and turn pink with age. They are in the shape of a narrow funnel and are shallow at in depth. The disk florets are each made up of , collectively a '' corolla'', which open into 5 lanceolate lobes comprising less than of the depth of the floret. Disk florets in the ''Symphyotrichum'' genus are bisexual, each with both male (stamen, anthers, and filaments) and female reproductive parts; thus, a disk floret produces pollen and can develop a seed.

Rice button aster (Symphyotrichum dumosum) (6435495559).jpg, Flower head showing ray and disk florets
Symphyotrichum dumosum 107676031.jpg, Involucre, phyllaries, and bracts
Symphyotrichum dumosum 108257760.jpg, Involucre, phyllaries, and bracts

Chromosomes

''Symphyotrichum dumosum'' has a chromosome number of ''x'' = 8. Diploid and tetraploid cytotypes with respective chromosome counts of 16 and 32 have been reported.

Taxonomy

This species was long known as ''Aster dumosus'' before it was moved into its current genus due to a phylogenetic analysis performed by American botanist Guy L. Nesom. The genus ''Aster'' has been narrowed considerably in scope in recent years, due to new information about the relationships of the species in the group.

''Symphyotrichum dumosum'' is classified in the subgenus ''Symphyotrichum'', section ''Symphyotrichum'', subsection ''Dumosi''. It is one of the "bushy asters and relatives." The word ''Symphyotrichum'' has as its root the Greek , which means "coming together," and , which means "hair." The specific epithet (second part of the scientific name) is Latin neuter case of and means "full of thornbushes" and "bushy" (rare).

Infraspecies

Although the following infraspecies are no longer accepted varieties according to Catalogue of Life (COL), Plants of the World Online (POWO), and World Flora Online (WFO), they were accepted by USDA PLANTS Database, NatureServe, and Integrated Taxonomic Information System (ITIS). The autonym is ''Symphyotrichum dumosum'' var. ''dumosum''.

*''Symphyotrichum dumosum'' var. ''gracilipes''
*''Symphyotrichum dumosum'' var. ''pergracile''
*''Symphyotrichum dumosum'' var. ''strictior''
*''Symphyotrichum dumosum'' var. ''subulifolium''

Distribution and habitat

Distribution

''Symphyotrichum dumosum'' has a recorded native presence in the wild in the Canadian province of Ontario, and in the United States in all states east of the Mississippi River except Vermont, as well as west of the Mississippi River in Iowa, Missouri, Oklahoma, Arkansas, Texas, and Louisiana. It is also native on the Caribbean island of Hispaniola.

It is an introduced species in New Brunswick, and in the countries of Belgium, France, Great Britain, Poland, Romania, and Switzerland. It is not on the European Union's List of invasive alien species of Union concern.

Habitat

''Symphyotrichum dumosum'' is categorized on the United States National Wetland Plant List (NWPL) with Wetland Indicator Status Rating of Facultative (FAC), choosing wetlands or non-wetlands and adjusting accordingly.

Conservation

, NatureServe lists ''Symphyotrichum dumosum'' as Secure (G5) worldwide with notation that the global status was last reviewed in 1985. Some North American province and state statuses are as follows: Presumed Extirpated (SX) in Iowa, Possibly Extirpated (SH) in Maine, Critically Imperiled (S1) in Pennsylvania, Imperiled (S2) in Ontario and Ohio, and Vulnerable (S3) in New York and Florida.

Gallery

Mason Wasp on Bushy Aster (5250200700).jpg, Mason wasp on flower head
Symphyotrichum dumosum 107676048.jpg, Stem and flower head
Honey Bee on Symphyotrichum dumosum (6435501395).jpg, Honey bee on flower head
Symphyotrichum dumosum 105499607.jpg, Cluster or small colony of ''S. dumosum''

Notes

Citations

References

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{{Taxonbar, from1=Q4050490, from2=Q7061674

dumosum
Flora of the United States
Flora of Ontario
Plants used in traditional Native American medicine
Plants described in 1753
Taxa named by Carl Linnaeus