Thalictrum cooleyi
Encyclopedia
Thalictrum cooleyi is a rare species of flowering plant in the buttercup family
known by the common name Cooley's meadowrue. It is native to the southeastern United States, where it is present in North Carolina
, Georgia
, and Florida
. It is threatened by habitat destruction and degradation. It is a federally listed endangered species
of the United States.
This perennial herb produces long, slender stems up to 2 meters long, sometimes growing erect. The leaves are each made up of several narrow leaflets, and some of the leaflets are divided further into lobes. Leaves near the base of the plant are borne on petioles
. The inflorescence
is a raceme
or a panicle
containing a few flowers each. The species is dioecious
, with male and female flowers occurring on separate plants. The flower lacks petals. It has four or five sepal
s which are white or yellowish in the male flower and greenish in the female. The male to female ratio
is 3:1. Blooming occurs in June and July.
There are nine populations of this plant consisting of 32 subpopulations. Twenty-four of the subpopulations are located in North Carolina and there is one in Florida. Seven subpopulations of plants have been recently discovered in Georgia; these are treated as members of this species but their taxonomy
is not certain.
This plant grows in the Atlantic coastal plain
province
. It grows in open, moist habitat types such as savanna
s, bog
s, and swamp forests. The soil is generally a sandy loam
which is neutral or slightly acidic
and wet at least part of the year. The plant can be found in spots that are moist or saturated but have no standing water. The plant also requires sun. The habitat is maintained by disturbance that keeps it clear of encroaching vegetation. Naturally this occurs during periodic wildfire
s. In the absence of a normal fire regime
the plant grows in areas that are kept clear and open by other means, including human activities such as mowing. The plant may occur on roadsides, an area of high disturbance. Plants growing in deep shade are stunted. They also have less erect stems and delayed flowering. Sunny areas that have recently burned produce the most robust plants.
Threats to the species include habitat degradation in areas where fire suppression is practiced. In these areas ecological succession
occurs and large, woody vegetation moves in. The meadowrue and other herbs are shaded out or outcompeted
. Habitat has been claimed for silviculture
operations, and the plant cannot grow in these converted areas. While the plant is more likely to occur in disturbed areas, it does not tolerate severe disturbance such as bulldozing or herbicide
application.
Ranunculaceae
Ranunculaceae are a family of about 1700 species of flowering plants in about 60 genera, distributed worldwide....
known by the common name Cooley's meadowrue. It is native to the southeastern United States, where it is present in North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, and Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. It is threatened by habitat destruction and degradation. 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...
of the United States.
This perennial herb produces long, slender stems up to 2 meters long, sometimes growing erect. The leaves are each made up of several narrow leaflets, and some of the leaflets are divided further into lobes. Leaves near the base of the plant are borne on petioles
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
. 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 a raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
or a panicle
Panicle
A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....
containing a few flowers each. The species is dioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, with male and female flowers occurring on separate plants. The flower lacks petals. It has four or five sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s which are white or yellowish in the male flower and greenish in the female. The male to female ratio
Ratio
In mathematics, a ratio is a relationship between two numbers of the same kind , usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second In mathematics, a ratio is...
is 3:1. Blooming occurs in June and July.
There are nine populations of this plant consisting of 32 subpopulations. Twenty-four of the subpopulations are located in North Carolina and there is one in Florida. Seven subpopulations of plants have been recently discovered in Georgia; these are treated as members of this species but their taxonomy
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
is not certain.
This plant grows in the Atlantic coastal plain
Atlantic Coastal Plain
The Atlantic coastal plain has both low elevation and low relief, but it is also a relatively flat landform extending from the New York Bight southward to a Georgia/Florida section of the Eastern Continental Divide, which demarcates the plain from the ACF River Basin in the Gulf Coastal Plain to...
province
Physiographic province
A physiographic province is a geographic region with a specific geomorphology and often specific subsurface rock type or structural elements.A continent may be subdivided into various physiographic provinces, each having a specific character, relief, and environment which contributes to its...
. It grows in open, moist habitat types such as savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
s, bog
Bog
A bog, quagmire or mire is a wetland that accumulates acidic peat, a deposit of dead plant material—often mosses or, in Arctic climates, lichens....
s, and swamp forests. The soil is generally a sandy loam
Loam
Loam is soil composed of sand, silt, and clay in relatively even concentration . Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils...
which is neutral or slightly acidic
Soil pH
The soil pH is a measure of the acidity or basicity in soils. pH is defined as the negative logarithm of the activity of hydrogen ions in solution. It ranges from 0 to 14, with 7 being neutral. A pH below 7 is acidic and above 7 is basic. Soil pH is considered a master variable in soils as it...
and wet at least part of the year. The plant can be found in spots that are moist or saturated but have no standing water. The plant also requires sun. The habitat is maintained by disturbance that keeps it clear of encroaching vegetation. Naturally this occurs during periodic wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
s. In the absence of a normal fire regime
Fire regime
A fire regime is the pattern, frequency and intensity of the bushfires and wildfires that prevails in an area. It is an integral part of fire ecology, and renewal for certain types of ecosystems. If fires are too frequent, plants may be killed before they have matured, or before they have set...
the plant grows in areas that are kept clear and open by other means, including human activities such as mowing. The plant may occur on roadsides, an area of high disturbance. Plants growing in deep shade are stunted. They also have less erect stems and delayed flowering. Sunny areas that have recently burned produce the most robust plants.
Threats to the species include habitat degradation in areas where fire suppression is practiced. In these areas ecological succession
Ecological succession
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...
occurs and large, woody vegetation moves in. The meadowrue and other herbs are shaded out or outcompeted
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...
. Habitat has been claimed for silviculture
Silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...
operations, and the plant cannot grow in these converted areas. While the plant is more likely to occur in disturbed areas, it does not tolerate severe disturbance such as bulldozing or herbicide
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
application.