Arenaria norvegica, also known as Arctic, English or Norwegian sandwort, is a low growing plant in the pink family, Caryophyllaceae

Caryophyllaceae

The Caryophyllaceae, commonly called the pink family or carnation family, is a family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranthaceae, Cactaceae and Polygonaceae...

, found in northwest Europe. The chromosome number is 2n=80. There are two recognised subspecies.

Description

A. norvegica is a much branched, low-growing plant growing up to six centimetres tall. The midrib of the leaves is indistinct and the margins glabrous only in the lower third which distinguishes it from the rather similar Arenaria ciliata

Arenaria ciliata

Arenaria ciliata is a perennial herb of the family Caryophyllaceae. A. ciliata is a calcicole occurring in open grassland and on bare rock in mountainous areas.-Distribution:...

.

Arenaria norvegica subsp. anglica
A. norvegica subsp. anglica is an annual

Annual plant

An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...

 or biennial

Biennial plant

A biennial plant is a flowering plant that takes two years to complete its biological lifecycle. In the first year the plant grows leaves, stems, and roots , then it enters a period of dormancy over the colder months. Usually the stem remains very short and the leaves are low to the ground, forming...

 herb with few non-flowering shoots. The leaves are opposite, narrowly ovate or elliptic. The flowers are eleven to twenty-three millimetres in diameter, have five white petals and three styles. The plant flowers from May to October.

Arenaria norvegica subsp. norvegica
A. norvegica subsp. norvegica is a perennial

Perennial plant

A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

 herb with many non-flowering shoots. The leaves are obovate and the white flowers about ten centimetres across with five petals and three to five styles.

Distribution

Both subspecies are uncommon and localised.

A. norvegica subsp. anglica is restricted to limestone regions in the Yorkshire Dales

Yorkshire Dales

The Yorkshire Dales is the name given to an upland area in Northern England.The area lies within the historic county boundaries of Yorkshire, though it spans the ceremonial counties of North Yorkshire, West Yorkshire and Cumbria...

 in the United Kingdom.

A. norvegica subsp. norvegica is found in west and northwest 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...

, the Shetland Isles, western 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...

, and Scandinavia

Scandinavia

Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...

  and Iceland

Iceland

Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

.

Habitat

Arenaria norvegica subsp. anglica favours thin peaty soil

Peat

Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...

s in cracks, depressions or hollows on 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....

 rock. It is also found growing in moist calcareous

Calcareous

Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...

 flushes and in gritty soil at the edge of tracks. It typically grows among small sedges

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...

, fescue

Fescue

Festuce is a genus of about 300 species of perennial tufted grasses, belonging to the grass family Poaceae . The genus has a cosmopolitan distribution, although the majority of the species are found in cool temperate areas...

 grass and other members of the pearlwort

Sagina

Sagina is a genus of 20–30 species of flowering plants in the family Caryophyllaceae. These are flowering herbs native to temperate regions of the Northern Hemisphere extending south to tropical mountain areas at high altitudes, reaching just south of the equator in Africa...

 and sandwort

Arenaria (plant)

Arenaria is a genus of flowering plants, within the family Caryophyllaceae.Species of this genus are among those plants commonly known as "sandworts". Several species formerly classified within Arenaria are now classed in the genera Spergularia, Eremogone and Minuartia.Species include:*Arenaria...

 genera. It is classified as a vulnerable endemic species in the vascular plant British Red Data Book.

Arenaria norvegica subsp. norvegica is found on sandy and gravelly substrates and is also restricted to limestone.