DECURRENT FALSE ASTER - Boltonia decurrens
![[Photo of Decurrent false aster]](images/aster2.gif)
Decurrent false aster, sometimes know as false starwort, is a big river floodplain species. Populations of decurrent false aster have declined as wetlands have been drained and converted to agricultural crop production. Decurrent false aster is listed ENDANGERED by the Missouri Department of Conservation and THREATENED by the U.S. Fish and Wildlife Service.
Identification
![[line drawing of Decurrent false aster]](images/aster1.gif)
Decurrent false aster is a perennial plant that grows one to five feet tall and occasionally reaches heights of over six feet. It blooms from July to October and bears seeds from August to October. Leaves are linear and narrow and have a blue tint. The lower leaves are broader and larger.
This plant is called "decurrent" because the leaf tissue extends down the stem from the point of leaf attachment. The flowers are about the size of a quarter. They occur in branched groups of composite heads with yellow disk flowers and white to purplish ray flowers.
Decurrent false aster is closely related to Boltonia asteroides var. recognita, which is a common weedy species of false aster. It is sometimes found in the same habitat with decurrent false aster; however, it lacks decurrent leaves.
For a technical description of this plant, refer to:
Steyermark, J.A. 1963. Flora of Missouri. Iowa State Press. Ames, Iowa. 1728 pp.
Habitat and Distribution
![[Missouri map of Decurrent false aster distribution]](images/momap.gif)
Decurrent false aster grows in wetlands, on the borders of marshes and lakes, and on the margins of bottomland oxbows and sloughs. Historically, this plant was found in wet prairies, marshes, and along the shores of some rivers and lakes. Decurrent false aster favors recently disturbed areas and flooding may play a role in maintaining its habitat. Current habitats include riverbanks, old fields, roadsides, mudflats and lake shores. Decurrent false aster prefers a moist habitat but can tolerate drought.
In Missouri, decurrent false aster distribution is restricted to the Mississippi River floodplain from the Illinois River southward. Current populations are fewer and more isolated than in historical times. Former distribution of this plant included Lincoln, St. Charles, St. Louis, and Cape Girardeau counties. Presently it is only known to occur in St. Charles County.
Cause of Historic Decline
Decurrent false aster is a weedy species restricted to the eastern floodplains of Missouri. Aster populations declined as floodplain wetlands were converted to agricultural lands. Pesticide use may have also added to population declines.
Currently, decurrent false aster occurs in association with agriculture and can be locally abundant in marginal, wet lowlands. Landowners can take an active role to protect this species in areas of marginal agricultural habitat.
Current Threats to Decurrent False Aster
- Habitat loss - The main threat to this plant is loss of suitable habitat. Decurrent false aster is restricted to floodplain wetlands and requires wet soils and soil disturbance. It also requires full sunlight. Populations decline as surrounding vegetation begins to compete with the aster. The amount of available habitat has been reduced by the conversion of wetlands to agricultural areas.
- Herbicides - Herbicide application in areas with decurrent false aster may cause populations to decline.
Protection and Management: Steps Toward Recovery
Many populations of the decurrent false aster are on public land, particularly on wetlands managed by the Army Corps of Engineers. These populations are being managed by participating state and federal agencies through periodic flooding and mowing.
A few populations occur on private land, often in association with agricultural crop production. The plant persists in wet, low areas and along the margins of converted wetlands. Recent floods have distributed seeds and exposed seed banks. Levees and roadsides may support small populations. It seems likely that additional populations occur on private land that are yet to be recorded.
Some private landowners voluntarily help manage the populations on private land. Private landowners can help by implementing the following suggestions.
- Protect wetlands - The wetland areas where decurrent false aster is found need to be protected in order to protect its habitat. Many aster populations are started when seeds float downstream and become established on river banks or in muddy backwater areas. Do not disturb these sites after flooding.
- Practice low intensity agriculture - Occasional cultivation may benefit asters through soil disturbance. Asters are often located in wet lowland agricultural fields. These marginal areas should be avoided in wet years unless woody vegetation becomes established. Periodic disturbance will be needed to keep a site suitable for the aster.
- Herbicides - Do not use herbicides in areas where the false aster is located or in areas that will drain into waterways and threaten plants downstream.
Other populations of decurrent false aster may already exist on private land. Reporting these areas to the Department of Conservation allows trained individuals to work with the landowner for the proper management of the endangered species.
Missouri and federal law prohibits the exportation, transportation, or sale of plants on the State or Federal lists.
For more information on decurrent false aster, or to report sightings of this species, contact:
Endangered Species Coordinator or Natural History Division Botanist Missouri Department of Conservation Natural History Division P.O. Box 180 Jefferson City, MO 65102 573/751-4115
For more information on pasture improvement programs or additional information about decurrent false aster management, contact:
Your Local Natural Resources Conservation Service Office
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