Dalea foliosa
Encyclopedia
Dalea foliosa is a species of flowering plant in the legume family
known by the common name leafy prairie clover. It is an endangered species
in the United States, where it occurs in three states: Illinois
, Tennessee
, and Alabama
. As of 1997 there were 51 occurrences, mostly within the state of Tennessee. Most of these are in very poor condition and the species is in decline.
This is a perennial herb growing 20 to 80 centimeters tall, with a number of erect stems sprouting from a hard root crown
. The leaves are each made up of hairless oval leaflets measuring up to 1.3 centimeters long. The inflorescence
is a cone-shaped or cylindrical spike of many purple flowers with pointed green bract
s between them. Blooming occurs in summer. The flowers are pollinated by bumblebee
s. The seeds can persist in a soil seed bank
for 8 years.
The plant is native to glades
and prairie
s with limestone
substrates. The habitat may be moist or wet with seeps
in the calcareous ground. It may grow alongside rose pink
(Sabatia angularis) and brown-eyed susan
(Rudbeckia triloba). In northern Illinois, where there are disjunct
occurrences of the plant, it can be found in sunny, open dolomite
prairies and river terraces that are periodically burned in the natural fire regime
.
This plant was much more widespread in the past. The main cause of its decline is the destruction and degradation of its habitat. Much of its habitat has been consumed for development and is now in industrial and commercial use. Remaining habitat is overgrazed
and invaded
by introduced plant species
such as Chinese privet (Ligustrum sinense) and Amur honeysuckle
(Lonicera maackii). Plants have been destroyed during road
maintenance and sewer
installation. In most areas, the plant grows in a habitat that requires periodic wildfire
for maintenance. Fire suppression efforts prevent this natural process and the habitat becomes overgrown with large and woody vegetation. The species is also fire-dependent because the seeds must be scarified
if they are to germinate
. Moisture is a limiting factor
for the plants once they do germinate. The plant apparently has a low rate of reproductive success
as few of the plants that germinate
survive. Many of the seedling
s are killed in dry summer conditions or frost heave
and only 5% of the plants that become seedlings reach the age of five years. The plant does not reproduce until it is 2 or 3 years old. Genetic diversity
is also low.
Some plants have been reintroduced to habitat where the species occurred in the past, including part of Indiana
.
Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
known by the common name leafy prairie clover. It is an 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...
in the United States, where it occurs in three states: Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, 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...
, and Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
. As of 1997 there were 51 occurrences, mostly within the state of Tennessee. Most of these are in very poor condition and the species is in decline.
This is a perennial herb growing 20 to 80 centimeters tall, with a number of erect stems sprouting from a hard root crown
Root crown
A root crown is that part of a root system from which a stem arises. Since roots and stems have quite different vascular anatomies, major vascular changes take place at this point....
. The leaves are each made up of hairless oval leaflets measuring up to 1.3 centimeters long. 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 cone-shaped or cylindrical spike of many purple flowers with pointed green bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s between them. Blooming occurs in summer. The flowers are pollinated by bumblebee
Bumblebee
A bumble bee is any member of the bee genus Bombus, in the family Apidae. There are over 250 known species, existing primarily in the Northern Hemisphere although they are common in New Zealand and in the Australian state of Tasmania.Bumble bees are social insects that are characterised by black...
s. The seeds can persist in a soil seed bank
Seed bank
Seed bank may refer to:*Seedbank, a repository of preserved seeds*The store of viable plant seed in an ecosystem; for example:** Soil seed bank, the viable seed present in the soil;...
for 8 years.
The plant is native to glades
Glade (geography)
A glade or clearing is an open area within a woodland. Glades are often grassy meadows under the canopy of deciduous trees such as red alder or quaking aspen in western North America. They also represent openings in forests where local conditions such as avalanches, poor soils, or fire damage have...
and prairie
Prairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
s with limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
substrates. The habitat may be moist or wet with seeps
Seep (hydrology)
A Seep is a moist or wet place where water, usually groundwater, reaches the earth's surface from an underground aquifer.-Description:Seeps are usually not of sufficient volume to be flowing beyond their above-ground location. They are part of the limnology-geomorphology system...
in the calcareous ground. It may grow alongside rose pink
Sabatia angularis
Sabatia angularis is a plant native to the United States.-External links:**...
(Sabatia angularis) and brown-eyed susan
Rudbeckia triloba
Rudbeckia triloba is a plant native to the United States. It is sometimes grown in gardens, but it is usually seen in old fields or along roadsides.Herbaceous biennial to weak perennial. Native to central-eastern United States...
(Rudbeckia triloba). In northern Illinois, where there are disjunct
Disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
occurrences of the plant, it can be found in sunny, open dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
prairies and river terraces that are periodically burned in the natural 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...
.
This plant was much more widespread in the past. The main cause of its decline is the destruction and degradation of its habitat. Much of its habitat has been consumed for development and is now in industrial and commercial use. Remaining habitat is overgrazed
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
and invaded
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
by introduced plant species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
such as Chinese privet (Ligustrum sinense) and Amur honeysuckle
Lonicera maackii
Lonicera maackii is a species of honeysuckle in the family Caprifoliaceae, native to temperate Asia in northern and western China , Mongolia, Japan , Korea, and southeastern Russia .It is listed as an endangered species in Japan...
(Lonicera maackii). Plants have been destroyed during road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
maintenance and sewer
Sewer
Sewer may refer to:* Part of sewerage, the infrastructure that conveys sewage*Effluent sewer, a collection system that transports only the liquid portion of wastewater through small-diameter pipes laid at contour...
installation. In most areas, the plant grows in a habitat that requires 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...
for maintenance. Fire suppression efforts prevent this natural process and the habitat becomes overgrown with large and woody vegetation. The species is also fire-dependent because the seeds must be scarified
Scarification (botany)
Scarification in botany involves cutting the seed coat using abrasion, thermal stress, or chemicals to encourage germination.-In botany:Scarification is a natural process important for germination of many species' seeds. This process involves the breaching of the natural seed coating by mechanical,...
if they are to germinate
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
. Moisture is a limiting factor
Limiting factor
A limiting factor or limiting resource is a factor that controls a process, such as organism growth or species population, size, or distribution. The availability of food, predation pressure, or availability of shelter are examples of factors that could be limiting for an organism...
for the plants once they do germinate. The plant apparently has a low rate of reproductive success
Reproductive success
Reproductive success is defined as the passing of genes onto the next generation in a way that they too can pass those genes on. In practice, this is often a tally of the number of offspring produced by an individual. A more correct definition, which incorporates inclusive fitness, is the...
as few of the plants that germinate
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
survive. Many of the seedling
Seedling
thumb|Monocot and dicot seedlingsA seedling is a young plant sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle , the hypocotyl , and the cotyledons...
s are killed in dry summer conditions or frost heave
Frost heaving
Frost heaving results from ice forming beneath the surface of soil during freezing conditions in the atmosphere. The ice grows in the direction of heat loss , starting at the freezing front or boundary in the soil...
and only 5% of the plants that become seedlings reach the age of five years. The plant does not reproduce until it is 2 or 3 years old. Genetic diversity
Genetic diversity
Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary....
is also low.
Some plants have been reintroduced to habitat where the species occurred in the past, including part of Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
.