''Pityopsis ruthii'' is a rare species of flowering plant 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 ...

known by the common name Ruth's golden aster. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the US state of

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

, where it is known only from

Polk County Polk County is the name of twelve counties in the United States, all except two named after president of the United States James Knox Polk: * Polk County, Arkansas * Polk County, Florida * Polk County, Georgia * Polk County, Iowa * Polk Count ...

. It is threatened by the modification of its habitat. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

Description

This is a perennial herb growing 10 to 30 centimeters tall from a

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

several centimeters in length. There are one to several erect, slender stems covered in silvery hairs. The basal leaves are lance-shaped and 3 or 4 centimeters long. Leaves on the stem are longer, overlapping, and silver-haired. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is an array of several

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 ...

on hairy, glandular branches. Each head has nine to eighteen yellow ray florets.''Pityopsis ruthii''.
Flora of North America

Habitat

This plant grows in soil that has accumulated in the cracks of riverbank boulders on two Tennessee rivers, the Hiwassee and

Ocoee River The Toccoa River and Ocoee River are the names in use for a single river that flows northwestward through the southern Appalachian Mountains of the southeastern United States. It is a tributary of the Hiwassee River, which it joins in Polk Coun ...

s.''Pityopsis ruthii''.
The Nature Conservancy. The rocks are subjected to periodic flooding when the river levels rise, submerging the plants and scouring the substrates they grow on.''Pityopsis ruthii''.
Center for Plant Conservation. The plants grow in nearly full sunlight and cannot tolerate much shade. The flooding and scouring action of the river water prevents the growth of other plants that might shade it out. The plant is associated with '' Liatris microcephala'' (smallhead blazing star), which tolerates the same kind of habitat. Other plants located near the aster include ''

Schizachyrium scoparium ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...

'' (little bluestem), ''

Andropogon gerardi ''Andropogon gerardi'', commonly known as big bluestem, is a species of tall grass native to much of the Great Plains and grassland regions of central and eastern North America. It is also known as tall bluestem, bluejoint, and turkeyfoot. Taxon ...

'' (big bluestem), '' Agalinis tenuifolia'' (slenderleaf false foxglove), '' Symphyotrichum dumosum'' (button aster), and '' Symphyotrichum undulatum'' (wavyleaf aster).Environmental Assessment: Experimental removal of competing vegetation from a population of Ruth's golden aster (''Pityopsis ruthii'') on the Hiwassee River.
USDA USFS.

Conservation

This river plant is threatened by a number of processes that affect its environment. The stretches of river where it occurs are downstream from

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, a ...

s. The

Apalachia Dam Apalachia Dam is a hydroelectric dam on the Hiwassee River in Cherokee County, in the U.S. state of North Carolina. The dam is the lowermost of three dams on the river owned and operated by the Tennessee Valley Authority, which built the dam in th ...

has eliminated the natural water regime in the Hiwassee River habitat. Water is now piped out of the river to a powerhouse and most of the flow comes from

tributaries A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage b ...

and runoff from surrounding hills.USFWS
Determination of End. Status for Pityopsis ruthii (Ruth's Golden Aster)
''Federal Register'' July 18, 1985.. This stoppage of the normal river flow has allowed plants to move into the small patches of soil occupied by the aster, leading to

competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...

and excessive shade. Troublesome competing plant species include ''

Toxicodendron radicans ''Toxicodendron radicans'', commonly known as eastern poison ivy or poison ivy, is an allergenic Asian and Eastern North American flowering plant in the genus ''Toxicodendron''. The species is well known for causing urushiol-induced contact derm ...

'' (poison ivy), ''

Parthenocissus quinquefolia ''Parthenocissus quinquefolia'', known as Virginia creeper, Victoria creeper, five-leaved ivy, or five-finger, is a species of flowering vine in the grape family, Vitaceae. It is native to eastern and central North America, from southeastern Ca ...

'' (Virginia creeper), ''

Vitis rotundifolia ''Vitis rotundifolia'', or muscadine, is a grapevine species native to the southern United States, southeastern and south-central United States. The growth range extends from Florida to New Jersey coast, and west to eastern Texas and Oklahoma. I ...

'' (wild grape), ''

Campsis radicans ''Campsis radicans'', the trumpet vine, yellow trumpet vine, or trumpet creeper (also known in North America as cow itch vine or hummingbird vine), is a species of flowering plant in the family Bignoniaceae, native to the eastern United States, ...

'' (trumpet creeper), ''

Lonicera japonica ''Lonicera japonica'', known as Japanese honeysuckle and golden-and-silver honeysuckle, is a species of honeysuckle native to eastern Asia. It is often grown as an ornamental plant, but has become an invasive species in a number of countries. Jap ...

'' (Japanese honeysuckle), '' Lespedeza cuneata'' (lespedeza), and ''

Microstegium vimineum ''Microstegium vimineum'', commonly known as Japanese stiltgrass, packing grass, or Nepalese browntop, is an annual plant, annual grass that is common in a wide variety of habitats and is well adapted to low light levels. Despite being non-nativ ...

'' (Nepal grass). Water is occasionally released from the dam when toxic

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

builds up and needs to be flushed out of the river. When the aster was placed on the endangered species list, its Hiwassee River population had declined 50% in eight years. Since then it has declined another 40% and all subpopulations are likely to become extinct within 50 years. The other population on the Ocoee River was composed of about 500 plants growing in a habitat affected by nearby

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

operations, as well as power production.Thomson, D. M. and M. W. Schwartz. (2006)
Using population count data to assess the effects of changing river flow on a endangered riparian plant.
''Conservation Biology'' 20(4) 1132-42. It is also located in an area that is subjected to trampling associated with

whitewater rafting Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a ...

recreation on the river. Despite these threats, the Ocoee population, recently counted at 593 plants, is considered to be secure for the time being. Conservation activities include propagation of the plant in

greenhouse A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of Transparent ceramics, transparent material, such as glass, in which plants requiring regulated climatic condit ...

s. This is made difficult by the infestation of the greenhouse plants by the

powdery mildew Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, as ...

Erysiphe cichoracearum ''Erysiphe cichoracearum'' is a fungal plant pathogen that causes powdery mildew disease of cucurbits, including melon, cucumber, pumpkin, and squash. The primary symptoms are white, powder-like spots on the leaves and stems. ''Sphaerotheca fu ...

''. The mildew is not present in the wild populations.Trigliano, R. N., et al. (2011)
First Report of Powdery Mildew on Ruth's Golden Aster (Pityopsis ruthii) Caused by ''Golovinomyces cichoracearum'' (''Erysiphe cichoracearum'').
''Plant Disease'' 95(7) 879.2. Competing vegetation has been increasing yearly, and this is likely causing a negative impact. The

Cherokee National Forest The Cherokee National Forest is a United States National Forest located in the U.S. states of Tennessee and North Carolina that was created on June 14, 1920. The forest is maintained and managed by the United States Forest Service. It encompasses ...

implemented a plan to remove poison ivy from aster sites, and though this was effective it was not feasible. Mechanical and chemical means are used to remove the vegetation.

References

External links

USDA Plants Profile
{{Taxonbar, from=Q7199561 Astereae Flora of Tennessee Polk County, Tennessee