Carex lutea
Encyclopedia
Carex lutea is a rare species of sedge
known by the common names golden sedge and sulphur sedge. It is endemic to North Carolina
, where it is known only from Pender
and Onslow Counties
in the Cape Fear River
watershed
. There are nine populations. The plant was discovered in 1991 and described to science as a new species in 1994, and it has not been thoroughly studied nor completely surveyed yet. Its rarity was obvious by 2002, however, when it was federally listed as an endangered species
.
This sedge was discovered in a very rare type of habitat made up of wet savannah
on coquina
limestone
substrate. It occurs on the edge of a swamp
y section of North Carolina's coastal plain
, and the sandy, acidic soil is either wet or submerged. This habitat experiences periodic wildfire
every few years which clears brush, creating an open canopy. This fire regime
is apparently vital to the rare Carex and other plants that cannot grow if the woody brush grows up and outcompetes them. Fire suppression efforts in the area threaten the plant and its ecosystem
; some of the populations occur on private land that is not allowed to burn. It generally does not grow in an area without periodic fires unless it is mowed to clear the brush or it is too wet for large woody vegetation to grow. Other threats include logging
and herbicide
use. Destruction of the habitat or alterations in its hydrology
could damage populations.
Despite its small numbers and habitat specificity, the sedge has a relatively high genetic diversity
compared to similar, more widespread species.
This plant is a perennial sedge forming clumps of narrow stems which may exceed 1 metres (3.3 ft) in height. The thin leaves are up to 28 centimetres (11 in) long. The staminate
(male) inflorescence
is a spike of flowers up to 4 cm (1.6 in) long, the spikelets clad in reddish brown or light brown scales. The pistillate
(female) inflorescence is under 3 cm (1.2 in) long and has yellow-green flowers that yield beaked fruits.
Carex
Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...
known by the common names golden sedge and sulphur sedge. It is endemic to 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...
, where it is known only from Pender
Pender County, North Carolina
-Demographics:As of the census of 2000, there were 41,082 people, 16,054 households, and 11,719 families residing in the county. The population density was 47 people per square mile . There were 20,798 housing units at an average density of 24 per square mile...
and Onslow Counties
Onslow County, North Carolina
-Demographics:As of the census of 2000, there were 150,355 people, 48,122 households, and 36,572 families residing in the county. The population density was 196 people per square mile . There were 55,726 housing units at an average density of 73 per square mile...
in the Cape Fear River
Cape Fear River
The Cape Fear River is a long blackwater river in east central North Carolina in the United States. It flows into the Atlantic Ocean near Cape Fear, from which it takes its name. The overall water quality of the river is continuously measured and monitored by and conducted by the , , and the...
watershed
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
. There are nine populations. The plant was discovered in 1991 and described to science as a new species in 1994, and it has not been thoroughly studied nor completely surveyed yet. Its rarity was obvious by 2002, however, when 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...
.
This sedge was discovered in a very rare type of habitat made up of wet savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
on coquina
Coquina
Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically sorted fragments of the shells of either molluscs, trilobites, brachiopods, or other invertebrates. For a sediment to be considered to be a coquina, the average size of the...
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....
substrate. It occurs on the edge of a swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
y section of North Carolina's coastal plain
Coastal plain
A coastal plain is an area of flat, low-lying land adjacent to a seacoast and separated from the interior by other features. One of the world's longest coastal plains is located in eastern South America. The southwestern coastal plain of North America is notable for its species diversity...
, and the sandy, acidic soil is either wet or submerged. This habitat experiences 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...
every few years which clears brush, creating an open canopy. This 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...
is apparently vital to the rare Carex and other plants that cannot grow if the woody brush grows up and outcompetes them. Fire suppression efforts in the area threaten the plant and its 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....
; some of the populations occur on private land that is not allowed to burn. It generally does not grow in an area without periodic fires unless it is mowed to clear the brush or it is too wet for large woody vegetation to grow. Other threats include logging
Logging
Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks.In forestry, the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard...
and 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...
use. Destruction of the habitat or alterations in its hydrology
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
could damage populations.
Despite its small numbers and habitat specificity, the sedge has a relatively high 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....
compared to similar, more widespread species.
This plant is a perennial sedge forming clumps of narrow stems which may exceed 1 metres (3.3 ft) in height. The thin leaves are up to 28 centimetres (11 in) long. The staminate
Stamen
The stamen is the pollen producing reproductive organ of a flower...
(male) 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 spike of flowers up to 4 cm (1.6 in) long, the spikelets clad in reddish brown or light brown scales. The pistillate
Gynoecium
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
(female) inflorescence is under 3 cm (1.2 in) long and has yellow-green flowers that yield beaked fruits.