Carex binervis
Encyclopedia
Carex binervis, the green-ribbed sedge, is a European species of sedge
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...

 with an Atlantic distribution. It is found from Fennoscandia
Fennoscandia
Fennoscandia and Fenno-Scandinavia are geographic and geological terms used to describe the Scandinavian Peninsula, the Kola Peninsula, Karelia and Finland...

 to the Iberian Peninsula
Iberian Peninsula
The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...

, and occurs in heath
Heath
-Habitats:* Heath or heathland, low-growing woody vegetation, mostly consisting of heathers and related species* Heaths in the British National Vegetation Classification system...

s, moorland
Moorland
Moorland or moor is a type of habitat, in the temperate grasslands, savannas, and shrublands biome, found in upland areas, characterised by low-growing vegetation on acidic soils and heavy fog...

 and other damp, acidic environments. It typically grows to a height of 15 centimetre, and has 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...

s comprising one male and several female spikes, each up to 45 mm (1.8 in) long. The utricles have two conspicuous green veins, which give rise to both the scientific name and the common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

 of the species. In the vegetative state, it closely resembles C. bigelowii, a species that usually grows at higher altitude. C. binervis was first described by James Edward Smith
James Edward Smith
Sir James Edward Smith was an English botanist and founder of the Linnean Society.Smith was born in Norwich in 1759, the son of a wealthy wool merchant. He displayed a precocious interest in the natural world...

 in 1800, and is classified in Carex sect. Spirostachyae
Carex sect. Spirostachyae
Carex sect. Spirostachyae is a section of the genus Carex, containing 38 species of sedge. Species in Carex sect. Spirostachyae share a suite of features, including the short internodes of the primary rhizomes, the presence of an antiligule, the leaf-like, sheathing bract at the base of the...

; several hybrids with other Carex species are known.

Vegetative parts

The culms of Carex binervis are 15 centimetre tall, although typically less than 120 centimetre. They are triangular in section with rounded corners and often a single furrow. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 are 7 centimetre long and 2–6 mm (0.078740157480315–0.236220472440945 ) wide, light green and shiny on the underside, but dark green and matt on the upper surface. The leaves are flat or slightly keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

ed, and taper abruptly to a fine point.

The roots of C. binervis are 1–2 mm (0.0393700787401575–0.078740157480315 ) in diameter, with the root hair
Root hair
A root hair, the rhizoid of a vascular plant, is a tubular outgrowth of a trichoblast, a hair-forming cell on the epidermis of a plant root. That is, root hairs are lateral extensions of a single cell and only rarely branched, thus invisible to the naked eye. They are found only in the region of...

s mostly occurring on the short lateral rootlets. The 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...

s run 25–40 mm (0.984251968503937–1.6 ) below the soil surface, and are light brown and approximately 6 mm (0.236220472440945 in) in diameter. The whole root system reaches a maximum depth of 18 cm (7.1 in), spreading more widely than Juncus squarrosus, another dominant plant in Atlantic wet heaths.

In the vegetative state, C. binervis is difficult to distinguish from C. bigelowii, a species that tends to grow at higher altitudes than C. binervis. They differ in that C. bigelowii has glaucous
Glaucous
Glaucous is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the Glaucous Gull , Glaucous-winged Gull , Glaucous Macaw , and Glaucous...

 leaves and purplish-brown scales on the rhizome, whereas C. binervis has orange-brown rhizome scales, and leaves which are not glaucous. The leaves of C. binervis also develop "wine-red" patches on aging, which are never seen in C. bigelowii.

Reproductive parts

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...

 of C. binervis may be up to half the length of the stem. The lower 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 resemble the leaves, while the upper bracts are more like the glumes. The inflorescence comprises a single terminal male spike, and 2–4 lateral female spikes. The male spike is 20–45 mm (0.78740157480315–1.8 ) long, with purplish glumes which are 4 millimetre long and have a paler midrib. The female spikes are 15–45 mm (0.590551181102362–1.8 ) long and cylindrical. Their peduncles
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...

 are half sheathed, and up to 10 cm (3.9 in) long, such that the lower female spikes tend to be nodding, while the upper female spikes are erect.

The utricles (seeds) of C. binervis are 3.5 millimetre long and broadly elliptical, with a rough, notched beak 1–1.5 mm (0.0393700787401575–0.0590551181102362 ) long. They are purplish brown or sometimes partly green, and both the plant's scientific and common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

s refer to the fact that the utricles are marked with two conspicuous green veins (from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 roots , "two", and , "nerve"). C. binervis has a chromosome number of 2n = 74.

Distribution and ecology

Carex binervis has an oceanic distribution, occurring only in areas of high rainfall, from Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

 and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

, through the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 and France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, to Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

. Within the British Isles, Carex binervis has a westerly and northerly distribution, and is more abundant in the Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

 and Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 than in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. Plants from Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...

 that were previously referred to C. binervis are now treated as a separate species, C. paulo-vargasii.

Carex binervis grows in acidic, siliceous environments, including "damp heath
Heath
-Habitats:* Heath or heathland, low-growing woody vegetation, mostly consisting of heathers and related species* Heaths in the British National Vegetation Classification system...

s, moors
Moorland
Moorland or moor is a type of habitat, in the temperate grasslands, savannas, and shrublands biome, found in upland areas, characterised by low-growing vegetation on acidic soils and heavy fog...

, rocky places and mountainsides"; together with species such as Deschampsia flexuosa
Deschampsia flexuosa
-Introduction:Deschampsia flexuosa Trin. or Wavy Hair-grass is a species of bunchgrass in the Poaceae family with a Holarctic distribution.-Habitat and distribution:...

, it is a "useful indicator of acid substrate". The species has been recorded at altitudes of up to 930 metres (3,051.2 ft) on Glyder Fach
Glyder Fach
Glyder Fach is a mountain in Snowdonia, north-west Wales, and is the second highest of the Glyderau and the sixth highest in Wales.Routes to the summit lead from Tryfan and Bristly Ridge to the north, via Glyder Fawr from Pen-y-Pass to the south, and along the Glyder ridge to the east, towards...

 in north Wales, and there are reports of occurrences up to 975 metre in the Scottish Highlands
Scottish Highlands
The Highlands is an historic region of Scotland. The area is sometimes referred to as the "Scottish Highlands". It was culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands...

. Although sedges are chiefly wind pollinated, insect pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

s have been observed to visit C. binervis occasionally.

Taxonomy

In 1800, James Edward Smith
James Edward Smith
Sir James Edward Smith was an English botanist and founder of the Linnean Society.Smith was born in Norwich in 1759, the son of a wealthy wool merchant. He displayed a precocious interest in the natural world...

 published an article in the Transactions of the Linnean Society of London, titled "Descriptions of five new British species of Carex", which included the first descriptions
Alpha taxonomy
Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...

 of Carex davalliana, C. binervis, C. tomentosa (a synonym of C. filiformis), C. micheliana (a synonym of C. flacca
Carex flacca
Carex flacca, with common names blue sedge, gray carex, glaucous sedge, or carnation-grass, , is a species of sedge native to parts of Europe and North Africa....

) and C. laevigata
Carex laevigata
Carex laevigata is a species of sedge. It lives in moist, shady environment in the lowlands of Western and Central Europe, particularly in alder–ash woodland. It is distinguished from similar species, such as C. binervis and C. distans by the presence of tiny red dots on the utricles...

. After the Latin diagnosis of Carex binervis, Smith writes:
This species appears to have been confounded with C. distans; and from Lightfoot's description of the green angles of the fruit, I presume it to have been what he intended under that name. It is considerably larger than the real distans, the spikes black intermixed with green rather than yellowish, and the female ones often branched or compounded at their base. Its most essential and decisive character however consists in the two strong deep-green nerves or ribs which run along each side of the fruit externally near the edge. The arillus is also broader and more compressed than in C. distans.


Carex binervis is classified in Carex subsection Elatae, part of Carex section Spirostachyae
Carex sect. Spirostachyae
Carex sect. Spirostachyae is a section of the genus Carex, containing 38 species of sedge. Species in Carex sect. Spirostachyae share a suite of features, including the short internodes of the primary rhizomes, the presence of an antiligule, the leaf-like, sheathing bract at the base of the...

, alongside C. laevigata and other species. Natural hybrids are known between C. binervis and various other Carex species, including C. laevigata (forming C. × deserta), C. viridula (forming C. × corstorphinei), C. punctata and C. flava.

External links

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