''Koenigia islandica'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of annual flowering plant in the buckwheat family,

Polygonaceae The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus '' Polygonum'', and was first used by Antoine Laurent de Jussieu in 1 ...

and is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the genus ''

Koenigia :Koenigia'' as described by Philibert Commerçon is a synonym of ''Dombeya. ''Koenigia'' is a genus of plants in the family Polygonaceae. The genus ''Aconogonon'' has been merged into ''Koenigia''. Description Species of ''Koenigia'' are annual ...

''. It is a very small plant and is found growing on wet gravel and scree in arctic tundra and alpine meadows.

Description

Koenigia islandica engler prantl cleaned

''Koenigia islandica'' is a minute, hairless,

annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...

with a slender taproot. It grows to a height of and is one of the world's smallest plants. It has simple or branched, often reddish, stems which root at the lower nodes. The leaves are in opposite pairs, fused at the base to a short sheath which surrounds the stem; the leaf blades are up to long, obovate, oblong or elliptic, with a blunt tip. The inflorescence is a few-flowered cyme with several bracts. The individual flowers are green, white or pinkish, bisexual, with three

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s, three

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s and three fused

carpels Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

. The fruit is a three-sided nut containing a single seed. Flowering occurs during July and August.

Distribution and habitat

''Koenigia islandica'' has a

circumboreal The Circumboreal Region in phytogeography is a floristic region within the Holarctic Kingdom in Eurasia and North America, as delineated by such geobotanists as Josias Braun-Blanquet and Armen Takhtajan. It is the largest floristic region in t ...

arctic/alpine distribution. Its range includes Northern Europe, Central and Northern Asia, North America, Greenland, and Southern Chile and Argentina. It is typically found growing on arctic tundra, on wet scree, on areas of wet gravel, near lakes, pools and streams, on alpine meadows and beside patches of melting snow, at altitudes of up to . In the United States, it is found in

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

and

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

. In Britain it is restricted to scattered locations on the

Isle of Skye The Isle of Skye, or simply Skye (; gd, An t-Eilean Sgitheanach or ; sco, Isle o Skye), is the largest and northernmost of the major islands in the Inner Hebrides of Scotland. The island's peninsulas radiate from a mountainous hub dominated ...

and the

Isle of Mull The Isle of Mull ( gd, An t-Eilean Muileach ) or just Mull (; gd, Muile, links=no ) is the second-largest island of the Inner Hebrides (after Skye) and lies off the west coast of Scotland in the Council areas of Scotland, council area of Arg ...

Ecology

On the island of

Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...

, ''Koenigia islandica'' is found on wet alluvial deposits, lake shores, and bare disturbed areas, growing on the black surface formed by mosses, liverworts and algal crust. It is one of only three annual vascular plants present on the island and the only common one, and with its range extending into the northern

arctic tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...

zone, it is considered the hardiest

in the world. Its success may be due to it being restricted to wet sites, which moderates the climate, making it warmer in cold weather and cooler in hot dry weather. Even when killed by heat or drought after flowering, the plant may wither and dry up, but the fruits can still produce viable seed. Dispersal of the seeds is by birds and water, and they can remain in the ground for years before germinating when the conditions are suitable.

References

{{Taxonbar, from=Q10895448 Polygonoideae Plants described in 1767