Pityopsis ruthii
Encyclopedia
Pityopsis ruthii is a rare species of flowering plant in the aster family
known by the common name Ruth's golden aster. It is endemic to the US state of Tennessee
, where it is known only from Polk County. It is threatened by the modification of its habitat. It is a federally listed endangered species
.
This is a perennial herb growing 10 to 30 centimeters tall from a rhizome
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
is an array of several flower heads
on hairy, glandular branches. Each head has nine to eighteen yellow ray florets.
This plant grows in soil that has accumulated in the cracks of riverbank boulders on two Tennessee rivers, the Hiwassee
and Ocoee Rivers. The rocks are subjected to periodic flooding when the river levels rise, submerging the plants and scouring the substrates they grow on. 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 (little bluestem), Andropgon gerardii (big bluestem), Agalinis tenuifolia (slenderleaf false foxglove), Symphyotricum dumosum (button aster), and Symphyotricum undulatum (wavyleaf aster).
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
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
and runoff from surrounding hills. 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
and excessive shade. Troublesome competing plant species include Toxicodendron radicans (poison ivy), Parthenocissus quinquefolia
(Virginia creeper), Vitis rotundifolia
(wild grape), Campsis radicans (trumpet creeper), Lonicera japonica (Japanese honeysuckle), Lespedeza cuneata
(lespedeza), and Microstegium vimineum
(Nepal grass). Water is occasionally released from the dam when toxic pollution
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
operations, as well as power production. It is also located in an area that is subjected to trampling associated with whitewater rafting 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
s. This is made difficult by the infestation of the greenhouse plants by the powdery mildew
Erysiphe cichoracearum
. The mildew is not present in the wild populations. Competing vegetation has been increasing yearly, and this is likely causing a negative impact. The Cherokee National Forest
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.
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
known by the common name Ruth's golden aster. It is endemic to the US state of Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
, where it is known only from Polk County. It is threatened by the modification of its habitat. It is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
This is a perennial herb growing 10 to 30 centimeters tall from a rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
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
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is an array of several flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
on hairy, glandular branches. Each head has nine to eighteen yellow ray florets.
This plant grows in soil that has accumulated in the cracks of riverbank boulders on two Tennessee rivers, the Hiwassee
Hiwassee River
The Hiwassee River has its headwaters on the north slope of Rocky Mountain in Towns County in northern Georgia and flows northward into North Carolina before turning westward into Tennessee, flowing into the Tennessee River a few miles west of State Route 58 in Meigs County, Tennessee...
and Ocoee Rivers. The rocks are subjected to periodic flooding when the river levels rise, submerging the plants and scouring the substrates they grow on. 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 (little bluestem), Andropgon gerardii (big bluestem), Agalinis tenuifolia (slenderleaf false foxglove), Symphyotricum dumosum (button aster), and Symphyotricum undulatum (wavyleaf aster).
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
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
s. The Apalachia Dam
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 the early 1940s to provide emergency power for...
has eliminated the natural water regime in the Hiwassee River habitat. Water is now piped out of the river to a powerhouse
Power station
A power station is an industrial facility for the generation of electric energy....
and most of the flow comes from tributaries
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...
and runoff from surrounding hills. 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 (biology)
Competition is an interaction between organisms or species, in which the fitness of one is lowered by the presence of another. Limited supply of at least one resource used by both is required. Competition both within and between species is an important topic in ecology, especially community ecology...
and excessive shade. Troublesome competing plant species include Toxicodendron radicans (poison ivy), Parthenocissus quinquefolia
Parthenocissus quinquefolia
Virginia creeper, five-leaved ivy, or five-finger is a woody vine native to eastern and central North America, in southeastern Canada, the eastern and central United States, eastern Mexico, and Guatemala, west as far as Manitoba, South Dakota, Utah and Texas.-Growth:It is a prolific climber,...
(Virginia creeper), Vitis rotundifolia
Muscadine
Muscadines are a grapevine species native to the present-day southeastern United States that has been extensively cultivated since the 16th Century. It differs from Vitis spp. in its number of chromosomes and its morphology...
(wild grape), Campsis radicans (trumpet creeper), Lonicera japonica (Japanese honeysuckle), Lespedeza cuneata
Lespedeza cuneata
Lespedeza cuneata is a species of flowering plant in the legume family known by the common names Chinese bushclover and sericea lespedeza, or just sericea...
(lespedeza), and Microstegium vimineum
Microstegium vimineum
Microstegium vimineum, commonly known as Japanese stiltgrass or Nepalese browntop, is an annual grass that is common in a wide variety of habitats and is well adapted to low light levels.-Geographic range:...
(Nepal grass). Water is occasionally released from the dam when toxic pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
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
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations, as well as power production. It is also located in an area that is subjected to trampling associated with whitewater rafting 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
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...
s. This is made difficult by the infestation of the greenhouse plants by the powdery mildew
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 fungi in the order Erysiphales. It is one of the easier diseases to spot, as its symptoms are quite distinctive. Infected plants display white powdery spots on the...
Erysiphe cichoracearum
Erysiphe cichoracearum
Erysiphe cichoracearum is a 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 fuliginea causes a similar looking powdery mildew of cucurbits.-...
. The mildew is not present in the wild populations. Competing vegetation has been increasing yearly, and this is likely causing a negative impact. The Cherokee National Forest
Cherokee National Forest
The Cherokee National Forest is a large National Forest created on July 19, 1936, by U.S. President Franklin Roosevelt, operated by the U.S. Forest Service and encompassing some 640,000 acres .-Location:...
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.