Twinflower (Linnaea borealis)

KingdomPlantae
PhylumAnthophyta
ClassMagnoliopsida
OrderDipsacales
FamilyCaprifoliaceae
GenusLinnaea
SizePlant length: up to 2m
Height: 5 - 15 cm

Classified as Nationally Scarce in the UK.

Twinflower is a member of the honeysuckle family and, like some of its relations, it is a creeper. However, twinflower grows much closer to the ground than honeysuckle, creeping beneath other low-growing plants with its thread-like stem. It is an evergreen perennial, with small oval leaves about a centimetre in length, and delicate bell-shaped flowers. As its name suggests, the flowers usually occur in pairs (although, there may only be one), drooping from a long stalk and coloured white or pink, with red stripes inside the bell.

The plant’s scientific name Linnaea refers to the fact that it was named in honour of the 18th century Swedish naturalist, Carl Linné, often called ‘the father of modern taxonomy’. Linné, who called himself ‘Linneaus’, developed the system that is still used to identify all species of plant, animal, fungus, single and simple multi-cell organisms and bacteria – the five Kingdoms of life on Earth. Every newly discovered organism (and newly discovered fossil) is identified and classified with two names (or three if it is discovered to be a variation of an existing species), derived from Latin or Greek. The names usually describe one of the species’ characteristics, (such as borealis – meaning ‘of the north’). A full classification of the species will place it in one of the five Kingdoms. From there, its other characteristics determine that species’ place within a number of other sub-categories (such as those shown above). Linneaus was typically self-deprecatory in response to the honour of having twinflower named after him. He wrote; "Linnaea was named by the celebrated Gronovius and is a plant of Lapland, lowly, insignificant and disregarded, flowering but for a brief space - from Linnaeus who resembles it."

Twinflower is found over Northern Europe, up to an altitude of 2,400 metres. It is also found in the Alps, and the Caucasus and Carpathian mountain ranges. In the UK, it is limited to the north-eastern part of Scotland where it still grows as a native plant, although there was a small introduced population in the north of England.

The plant occurs in both native and planted Scots pine woodland, preferring light shade and acidic soils.

Twinflower is a perennial, and the evergreen leaves last some two years before being shed and replaced. It can spread by seed or vegetatively, the seeds being dispersed by animals and birds, whilst new shoots come from plants at least five years old.

The plant is shallow-rooted, susceptible to both drought and fire, but it can re-establish itself on fire-damaged or disturbed ground. However, it is believed that the seeds do not survive for long within the seedbank. Twinflower has the ability to produce vegetative clones of itself, although these do not appear to be able to self-fertilise.

The main threats to twinflower come from damage during forestry operations, although some think it might improve the plant’s survival within an area through the dispersal of plant fragments. Overgrazing by sheep and deer can be a threat as well, although a lack of grazing can lead to the plants being crowded out by more dominant vegetation. There is also the risk of loosing small isolated populations of related plants.

The twinflower is listed as a priority species in the UK Biodiversity Action Plan (UK BAP). The plant is known to have declined considerably in recent years, and is now found on some 50 sites in north-east Scotland. There used to be a small population in northern England, thought to have arrived with pine seedlings.

Native pine woodland is categorised as a priority habitat under the UK Biodiversity Action Plan, and many populations of twinflower in Scotland are on designated sites, so the plant enjoys a fair measure of protection. There are also populations in cultivation, notably at the Royal Botanic Gardens, Edinburgh, and the botanic gardens of both Edinburgh and Aberdeen Universities. However, it is felt that more should be done to improve this attractive plant’s chances of survival in this country. A number of projects are underway to variously assess the true status of twinflower, and study the problems of sexual regeneration. This may include plans to re-locate specimens to different areas in an attempt to overcome the problem of non-fertilisation between plant clones, and help produce viable seed stock. There are hopes that more can be learned about the plant’s biology by exchanging information with botanists from other countries where twinflower grows.

The Forestry Commission are one of the partners working on the plans to conserve twinflower, and they are the main UK contact agency for this species. Plantlife Scotland and Scottish Natural Heritage are also engaged in research work for this attractive species.

The UK BAP Species Action Plan for twinflower is available on-line at:
www.ukbap.org.uk/
For more on endangered plants see Plantlife, the wild plant conservation charity:
http://www.plantlife.org.uk

Information supplied by English Nature.

http://www.english-nature.org.uk