# Linnaea

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***Linnaea borealis*** is a [species](/source/Species) of [flowering plant](/source/Flowering_plant) in the family [Caprifoliaceae](/source/Caprifoliaceae) (the honeysuckle family). It is the only species in the genus ***Linnaea***.[1] It is a [boreal](/source/Boreal_forest) to [subarctic](/source/Subarctic) woodland [subshrub](/source/Subshrub), commonly known as **twinflower** (sometimes written **twin flower**).

This plant was a favourite of [Carl Linnaeus](/source/Carl_Linnaeus), founder of the modern system of [binomial nomenclature](/source/Binomial_nomenclature), after whom the genus was named.

## Description

The [perennial](/source/Perennial_plant) stems of *Linnaea borealis* are slender, pubescent, and prostrate, growing to 20–40 centimetres (7.9–15.7 inches) long, with opposite [evergreen](/source/Evergreen) rounded oval [leaves](/source/Leaves) 3–10 millimetres (0.12–0.39 in) long and 2–7 mm (0.079–0.276 in) broad. The flowering stems curve erect, to 4–8 cm (1.6–3.1 in) tall, and are leafless except at the base. The [flowers](/source/Flower) are paired, pendulous, 7–12 mm (0.28–0.47 in) long, with a five-lobed, pale pink corolla.[2][3]

*L. borealis* is [self-incompatible](/source/Self-incompatibility_in_plants), requiring [cross-pollination](/source/Pollination) to produce viable [seeds](/source/Seed); since [pollen](/source/Pollen) dispersal is usually not far, individuals and clonal colonies can become reproductively isolated.[4] Regardless of seed production, *Linnaea* plants in a particular area often spread by [stolons](/source/Stolon) to form [clonal patches](/source/Vegetative_reproduction) of the same [genotype](/source/Genotype).

## Taxonomy

*Linnaea borealis* was first formally described by [Carl Linnaeus](/source/Carl_Linnaeus) in 1753 in *[Species Plantarum](/source/Species_Plantarum)*.[5] It was the sole species in the genus *Linnaea*. The genus name had been used earlier by the Dutch botanist [Jan Frederik Gronovius](/source/Jan_Frederik_Gronovius), and was given in honour of Linnaeus. Linnaeus adopted the name because *Linnaea borealis* was his favourite plant.[6]

*Linnaea borealis* is considered to be a single [circumboreal](/source/Circumboreal_Region) species, with three generally recognized subspecies:

- *Linnaea borealis* subsp. *borealis* - Europe
- *Linnaea borealis* subsp. *americana* - North America (formerly classified as the species *Linnaea americana*)
- *Linnaea borealis* subsp. *longiflora* - Asia, and western North America (from [Alaska](/source/Alaska) to [California](/source/California))

The English name "twinflower" for *Linnaea borealis* refers to the plant's paired flowers.

In 2013 Christenhusz *et al.* concluded that the genus *[Abelia](/source/Abelia)*, as then circumscribed, was polyphyletic, and proposed merging *Abelia* and several other genera in tribe Linnaeeae into *Linnaea*.[6] Wang, Landrein, *et al.* proposed reorganizing the tribe into several new and existing genera, and keeping *Linnaea* a monotypic genus.[7] The circumscription proposed by Wang, Landrein, *et al.* is currently accepted by [Plants of the World Online](/source/Plants_of_the_World_Online).[1][8]

## Distribution and habitat

*Linnaea borealis* has a circumpolar distribution in moist [subarctic](/source/Subarctic), boreal, or cool temperate [forests](/source/Forest), extending further south at higher elevations in various [mountains](/source/Mountain), in [Europe](/source/Europe) south to the [Alps](/source/Alps), in [Asia](/source/Asia) south to northern [Japan](/source/Japan), and in North America south to northern [California](/source/California) and to [Arizona](/source/Arizona) and [New Mexico](/source/New_Mexico) in the west, and to [West Virginia](/source/West_Virginia) (and formerly [Tennessee](/source/Tennessee)) in the [Appalachian Mountains](/source/Appalachian_Mountains) in the east.[9][10]

Clonal stands of *Linnaea* can be long-persisting, in some places remaining extant even if seed is not produced or if [seedling](/source/Seedling) germination or establishment does not occur.

The species was presumably common in areas south of its present range during times of [Pleistocene](/source/Pleistocene) ("Ice Age") glaciations, and its clone-forming perennial growth habit has allowed it to survive the subsequent millennia locally within this former range in various high-elevation or otherwise cool and moist habitats, including [algific talus slopes](/source/Algific_talus_slope) with persisting underground [periglacial](/source/Periglacial) ice.

## Conservation

While the three subspecies of *L. borealis* are all considered widespread, abundant, and secure in their main, northern ranges, all three subspecies are of conservation concern near the subspecies' range edges or at more southerly, [disjunct](/source/Disjunct_distribution) sites.

In [Great Britain](/source/Great_Britain), *L. borealis* ssp. *borealis* is listed as "nationally scarce", growing mainly in open [pine woodlands](/source/Caledonian_Forest) in [Scotland](/source/Scotland) and northernmost [England](/source/England). [Foresters](/source/Forester) consider this plant to be an [indicator species](/source/Indicator_species) of [ancient woodlands](/source/Ancient_woodland), often found in association with [creeping lady's tresses](/source/Creeping_lady's_tresses). It is found in about 50 sites around the country, with most situated in the woods around the [Cairngorms](/source/Cairngorms); the southernmost locations are four sites in [Northumberland](/source/Northumberland) and one in [County Durham](/source/County_Durham). The sparseness of the sites is responsible for the continued decline of the plant in the country. In [Scotland](/source/Scotland), 37% of *L. borealis* patches studied consisted of a single genotype, reproducing clonally [vegetatively](/source/Vegetative_reproduction) but not producing viable seed. This is a conservation concern because, without viable seed, the species may not be able to re-populate restored habitat, and may not be able to adapt to climate change by establishing new populations.[4]

In the [United States](/source/United_States), *L. borealis* ssp. *americana* is of conservation concern in several states along or near the southern edge of the species' range, including Arizona, [Iowa](/source/Iowa), [Massachusetts](/source/Massachusetts), [North Dakota](/source/North_Dakota), [Pennsylvania](/source/Pennsylvania), and West Virginia, and was known historically but now considered [extirpated](/source/Local_extinction) or possibly so in [Illinois](/source/Illinois), [Indiana](/source/Indiana), [New Jersey](/source/New_Jersey), [Ohio](/source/Ohio), [Rhode Island](/source/Rhode_Island), and Tennessee.

In [Canada](/source/Canada), *Linnaea borealis* ssp. *longiflora* is considered of conservation significance in the [Yukon](/source/Yukon) Territory, along the eastern edge of its range, where ssp. *americana* is widespread and abundant.

Since many of the outlying southern sites for *Linnaea borealis* are in habitats that are at high elevations or otherwise in cooler [microclimates](/source/Microclimates) than the surrounding general landscapes, ongoing and prospective [climate change](/source/Global_warming) has become a significant concern for the conservation of this species in such places, such as [Ice Mountain](/source/Ice_Mountain) in West Virginia, a low-elevation [algific talus slope](/source/Algific_talus_slope) with persisting buried ice.

## In culture

Linnaeus took *L. borealis* as his own personal symbol when he was raised to the Swedish nobility in 1757. In his **[Critica Botanica](/source/Critica_Botanica)** (1737), Linnaeus had used Gronovius' name *Linnaea* as an example to advocate the use of commemorative personal names as botanical names:

*it is commonly believed that the name of a plant which is derived from that of a botanist shows no connection between the two...[but]...Linnaea was named by the celebrated [Gronovius](/source/Jan_Frederik_Gronovius) and is a plant of Lapland, lowly, insignificant, disregarded, flowering but for a brief space — after Linnaeus who resembles it.*[11][12]

The flower of *Linnaea borealis* is the provincial flower of [Småland](/source/Sm%C3%A5land),[13] the home province of Linnaeus.

## References

1. "*Linnaea borealis* L.". 140689-2. Retrieved 12 January 2024.

1. Klinkenberg, Brian (ed.) (2014). ["*Linnaea borealis*"](http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Linnaea%20borealis). *E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca].*. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. Retrieved 2015-01-24.[dead link]

1. Giblin, David (ed.) (2015). ["*Linnaea borealis*"](http://biology.burke.washington.edu/herbarium/imagecollection.php?Genus=Linnaea&Species=borealis). *WTU Herbarium Image Collection*. Burke Museum, University of Washington. Retrieved 2015-01-24.

1. Scobie, A. R. & Wilcock, C. C. (2009). "Limited mate availability decreases reproductive success of fragmented populations of *Linnaea borealis*, a rare, clonal self-incompatible plant". *[Annals of Botany](/source/Annals_of_Botany)*. **103** (6): 835–846. [doi:10.1093/aob/mcp007](https://doi.org/10.1093/aob/mcp007). [PMC 2707897](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2707897). [PMID 19181748](https://pubmed.ncbi.nlm.nih.gov/19181748)

1. Christenhusz, Maarten J.M. (2013). "Twins are not alone: a recircumscription of Linnaea (Caprifoliaceae)". *Phytotaxa*. **125** (1): 25–32. [doi:10.11646/phytotaxa.125.1.4](https://doi.org/10.11646/phytotaxa.125.1.4)

1. Wang H-F, Landrein S, Dong W-P, Nie Z-L, Kondo K, Funamoto T, et al. (2015) Molecular Phylogeny and Biogeographic Diversification of Linnaeoideae (Caprifoliaceae s. l.) Disjunctly Distributed in Eurasia, North America and Mexico. PLoS ONE 10(3): e0116485. doi:10.1371/journal. pone.0116485

1. [*Abelia* R.Br.](https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30049036-2) *[Plants of the World Online](/source/Plants_of_the_World_Online)*. Retrieved 25 April 2024.

1. Sullivan, Steven. K. (2015). ["*Linnaea borealis*"](http://www.wildflowersearch.com/search?&PlantName=Linnaea+borealis). *Wildflower Search*. Retrieved 2015-01-24.

1. [Stafleu, Frans A.](/source/Frans_Stafleu) 1971. *Linnaeus and the Linnaeans: the Spreading of their Ideas in Systematic Botany, 1735–1789*. Utrecht: International Association for Plant Taxonomy. ISBN 90-6046-064-2. p. 83.

1. [Core, Earl L.](/source/Earl_Lemley_Core) (1975), *The Wondrous Year: West Virginia Through the Seasons*, [Grantsville](/source/Grantsville,_West_Virginia), West Virginia: [Seneca Books](/source/Seneca_Books), pg 45.

1. [Visit Småland](http://www.visitsmaland.se/web/Information.aspx) [Archived](https://archive.today/20120918230201/http://www.visitsmaland.se/web/Information.aspx) 2012-09-18 at archive.today Retrieved 25 February 2012.

- *The [Linnaeus Link Project](/source/Linnaeus_Link_Project)* in the spring 2005 edition of *Nature First*, the magazine for [Natural History Museum](/source/Natural_History_Museum,_London) members.
- *Species and habitat conservation* from Plantlife.org.uk [\[1\]](https://web.archive.org/web/20120313122916/http://www.plantlife.org.uk/html/species_and_conservation/species_and_conservation_bfb_casestudies.htm#twinflower) and [\[2\]](https://web.archive.org/web/20120313122927/http://www.plantlife.org.uk/html/scotland/Scotland3yearspage2.htm#twinflower)
- Twinflower species profile [\[3\]](https://web.archive.org/web/20120705015915/http://www.treesforlife.org.uk/tfl.twinflower.html)

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Adapted from the Wikipedia article [Linnaea](https://en.wikipedia.org/wiki/Linnaea) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Linnaea?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.