Physaria filiformis
Encyclopedia
Physaria filiformis is a rare species of flowering plant in the mustard family
known by the common names Missouri bladderpod and limestone glade bladderpod. It is native to Missouri
and Arkansas
in the United States. It was federally listed as an endangered species
in 1987 and it was downlisted to threatened status in 2003.
This is an annual herb producing several slender, branching stems up to 25 centimeters tall, growing erect or drooping. The leaves vary in shape, and the basal ones reach 2.4 centimeters in length. The inflorescence
is a raceme
of pale yellow flowers with petals half a centimeter to nearly one centimeter long. The fruit is a spherical silique
. The plant is a winter annual, sprouting and forming a basal rosette of leaves in the fall and then producing stems and flower the following spring. Seeds are dispersed
on the wind and in surface runoff
.
This plant grows in limestone
glade
s and outcrop
s of bare bedrock
in southwestern Missouri and northwestern Arkansas. The surrounding habitat may be prairie
and pasture
. Several types of forest
may be adjacent to the glades. The soil is shallow on the glades and supports few other plants. The plant grows less often in more vegetated areas with deeper soils, probably because other plants successfully compete
with it there. It is also less abundant in the shady understory
of Juniperus virginiana
forest, as sunlight is a limiting factor
in its growth. It can be found in a number of microhabitats, a factor that is important in its management and conservation. Wildfire
is important in the maintenance of the limestone glade habitat and even moreso its surrounding ecotone
s. Fire is the mechanism that keeps these habitats open and free of large and woody vegetation that shade out small annuals. Fire prevents ecological succession
in the open habitat where the plant grows. Other plants in the local habitat include Arenaria petula, Camassia scilloides
, Northoscordum bivalve, Opuntia humifusa, Satureja arkansana, Tradescantia tharpii, and Verbena canadensis.
As the health of the local ecosystem
depends on fire, the practice of fire suppression has caused the degradation of the habitat. When fire is prevented, woody vegetation moves in, covering the glades and blocking the light from reaching this small plant. This encroachment of surrounding vegetation is a main threat to the species. Other threats include off-road vehicle
s, limestone mining, and urban development. Invasive species
of plants have been introduced to the habitat, including Bromus tectorum, a competitive grass
. The plant may be affected by grazing
, trampling, and other disturbance, but these threats are mild because the plant can tolerate light disturbance.
When this plant was designated an endangered species there were nine populations. Extensive surveys located more occurrences and many of these were put under the protection of a number of agencies, including the National Park Service
and The Nature Conservancy
. By 2003 there were about 60 populations and the outlook for the plant had improved enough to warrant its downlisting to threatened status.
Most occurrences of the plant are in southwestern Missouri. A large population can be found at Wilson's Creek National Battlefield
. Conservation activities include protection of the habitat in public areas, prescribed burns to replace the natural fire regime
, and reduced use of herbicide
s.
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
known by the common names Missouri bladderpod and limestone glade bladderpod. It is native to Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
and Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
in the United States. It was federally listed as 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 1987 and it was downlisted to threatened status in 2003.
This is an annual herb producing several slender, branching stems up to 25 centimeters tall, growing erect or drooping. The leaves vary in shape, and the basal ones reach 2.4 centimeters in length. 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...
of pale yellow flowers with petals half a centimeter to nearly one centimeter long. The fruit is a spherical silique
Silique
A silique or siliqua is a fruit of 2 fused carpels with the length being more than three times the width. The outer walls of the ovary usually separate when ripe, leaving a persistent partition...
. The plant is a winter annual, sprouting and forming a basal rosette of leaves in the fall and then producing stems and flower the following spring. Seeds are dispersed
Seed dispersal
Seed dispersal is the movement or transport of seeds away from the parent plant. Plants have limited mobility and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors. Seeds can be dispersed away from the parent plant...
on the wind and in surface runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
.
This plant grows in 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....
glade
Glade
-Geography:*Glade , open area in woodland, synonym for "clearing"**Glade skiing, skiing amongst treesPlaces in the United States*Glade, California, a former town in Lassen County*Glade, Kansas, a city in Phillips County...
s and outcrop
Outcrop
An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...
s of bare bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...
in southwestern Missouri and northwestern Arkansas. The surrounding habitat may be 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...
and pasture
Pasture
Pasture is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep or swine. The vegetation of tended pasture, forage, consists mainly of grasses, with an interspersion of legumes and other forbs...
. Several types of forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
may be adjacent to the glades. The soil is shallow on the glades and supports few other plants. The plant grows less often in more vegetated areas with deeper soils, probably because other plants successfully compete
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...
with it there. It is also less abundant in the shady understory
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
of Juniperus virginiana
Juniperus virginiana
Juniperus virginiana is a species of juniper native to eastern North America, from southeastern Canada to the Gulf of Mexico, east of the Great Plains...
forest, as sunlight 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...
in its growth. It can be found in a number of microhabitats, a factor that is important in its management and conservation. 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...
is important in the maintenance of the limestone glade habitat and even moreso its surrounding ecotone
Ecotone
An ecotone is a transition area between two biomes but different patches of the landscape, such as forest and grassland. It may be narrow or wide, and it may be local or regional...
s. Fire is the mechanism that keeps these habitats open and free of large and woody vegetation that shade out small annuals. Fire prevents 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...
in the open habitat where the plant grows. Other plants in the local habitat include Arenaria petula, Camassia scilloides
Camassia scilloides
Camassia scilloides is a perennial herb also known as the Atlantic camas and Southern Wild Hyacinth. It is native to the eastern half of North America...
, Northoscordum bivalve, Opuntia humifusa, Satureja arkansana, Tradescantia tharpii, and Verbena canadensis.
As the health of the local ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
depends on fire, the practice of fire suppression has caused the degradation of the habitat. When fire is prevented, woody vegetation moves in, covering the glades and blocking the light from reaching this small plant. This encroachment of surrounding vegetation is a main threat to the species. Other threats include off-road vehicle
Off-road vehicle
An off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with deep, open treads, a flexible suspension, or even caterpillar tracks...
s, limestone mining, and urban development. Invasive species
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....
of plants have been introduced to the habitat, including Bromus tectorum, a competitive grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
. The plant may be affected by grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
, trampling, and other disturbance, but these threats are mild because the plant can tolerate light disturbance.
When this plant was designated an endangered species there were nine populations. Extensive surveys located more occurrences and many of these were put under the protection of a number of agencies, including the National Park Service
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...
and The Nature Conservancy
The Nature Conservancy
The Nature Conservancy is a US charitable environmental organization that works to preserve the plants, animals, and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive....
. By 2003 there were about 60 populations and the outlook for the plant had improved enough to warrant its downlisting to threatened status.
Most occurrences of the plant are in southwestern Missouri. A large population can be found at Wilson's Creek National Battlefield
Wilson's Creek National Battlefield
Wilson's Creek National Battlefield at 6424 West Farm Road 182 near Republic, Missouri, preserves the site of the Battle of Wilson's Creek. Fought on August 10, 1861, it was the first major American Civil War engagement west of the Mississippi River. The Confederate's failure to exploit their...
. Conservation activities include protection of the habitat in public areas, prescribed burns to replace 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...
, and reduced use of 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...
s.