''Pityopsis ruthii'' is a rare species of flowering plant in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

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

endemic Endemism is the state of a species being found only 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 foun ...

to the US state of

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

, where it is known only from Polk County. 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, 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 Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

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 In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is an array of several

flower heads A pseudanthium (; : pseudanthia) 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, composite flowers ...

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 Co ...

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 ''Symphyotrichum dumosum'' (formerly ''Aster dumosus'') is a species of flowering plant of the Family (botany), family Asteraceae commonly known as rice button aster and bushy aster. It is Native plant, native to much of eastern and central No ...

'' (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, aqua ...

s. The Apalachia Dam 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 an ''affluent'', is a stream or river that flows into a larger stream ('' 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 into which the ...

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, indi ...

and excessive shade. Troublesome competing plant species include ''

Toxicodendron radicans ''Toxicodendron radicans'', commonly known as eastern poison ivy or poison ivy, is a species of allergenic flowering plant. It has numerous subtaxons and forms both vines and shrubs. Despite its common name, it is not a true ivy, but rather a m ...

'' (poison ivy), ''

Parthenocissus quinquefolia ''Parthenocissus quinquefolia'', commonly known as Virginia creeper, woodbine, five-leaved ivy, or five-finger, is a species of flowering vine in the grape family Vitaceae. The species is native to eastern and central North America, with its r ...

'' (Virginia creeper), ''

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

'' (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 trumpet vine family Bignoniaceae, native to eastern North ...

'' (trumpet creeper), ''

Lonicera japonica ''Lonicera japonica'', known as Japanese honeysuckle and golden-and-silver honeysuckle, is a species of honeysuckle native to East Asia, including many parts of China. It is often grown as an ornamental plant, but has become an invasive species i ...

'' (Japanese honeysuckle), ''

Lespedeza cuneata ''Lespedeza cuneata'' is a species of flowering plant in the Fabaceae, legume family known by the common names Chinese bushclover and sericea lespedeza, or just sericea.Gucker, Corey. (2010) (Revised from Munger, Gregory T., 2004)''Lespedeza cune ...

'' (lespedeza), and ''

Microstegium vimineum ''Microstegium vimineum'', commonly known as Japanese stiltgrass, packing grass, or Nepalese browntop, is an annual grass that is common in a wide variety of habitats and is well adapted to low light levels. It has become an invasive species thr ...

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

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

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 Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

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 is a structure that is designed to regulate the temperature and humidity of the environment inside. There are different types of greenhouses, but they all have large areas covered with transparent materials that let sunlight pass an ...

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

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

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. '' Sphaerothec ...

''. 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 encompas ...

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