Lavatera arborea
Encyclopedia
Lavatera arborea the Tree Mallow, is a species of mallow native to the coast
s of western Europe
and the Mediterranean region, from the British Isles
south to Algeria
and Libya
, and east to Greece
.
It is a shrub
by annual
, biennial
or perennial plant
growing to 0.5–2 m (rarely 3 m) tall. The leaves
are orbicular, 8–18 cm diameter, palmately lobed with five to nine lobes, and a coarsely serrated margin. The flower
s are 3–4 cm diameter, dark pink to purple and grow in fasciculate axillary clusters of two to seven. It grows mainly on exposed coastal locations, often on small island
s, only rarely any distance inland.
Although long considered a species of Lavatera
, genetic and morphological analysis by Martin Forbes Ray, reported in 1998, suggested it was better placed in the genus Malva
, in which it was named Malva dendromorpha M.F.Ray. However the earlier name Malva arborea L. (Webb & Berthol.) was validly published and has priority over Malva dendromorpha.
tolerance is thought to be improved by soil with higher phosphate
content, making guano
enrichment particularly beneficial.
to the affected area. It is theorised that lighthouse
keepers may have spread the plant to some British islands for use as a poultice and to treat burns, an occupational hazard.
Thought to have been used as an alternative to toilet paper. The seeds are edible and are known in Jersey as "petit pains", or "little breads".
Tree Mallow was considered a nutritive animal food in Britain in the 19th century, and is still sometimes used as animal fodder
in Europe.
Lavatera arborea has long been cultivated in British gardens, as described in the 1835 self-published book British Phaenogamous Botany, which used the then-common name Sea Tree-mallow: "This species is frequently met with in gardens, where, if it is allowed to scatter its seeds, it will spring up for many successive years, and often attain a large size. The young plants will, as Sir J. E. Smith observes, now and then survive one or more mild Winters; but having once blossomed it perishes."
While sometimes detrimental to seabird habitat, management of Tree Mallow (both planting and thinning) has been successfully employed to shelter nesting sites of the threatened Roseate Tern
, which requires more coverage than Common Tern
s to impede predation.
The Tree Mallow's recent increased range among Scottish islands has raised concerns that it is displacing native vegetation, and is reducing Atlantic Puffin
(Fratercula arctica) populations in affected areas. The plant forms dense stands along the island coasts that inhibit breeding, and causes the puffins to abandon their burrows.
Its spread among Australian islands in recent decades is thought to be reducing biodiversity, soil retention, and seabird habitat. According to one study, "Crested and Caspian Terns that nest in the open are closed out by the canopy, and Little Penguins (Eudyptula minor) and Bridled Terns (Sterna anaethetus) are excluded by the lack of undergrowth".
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
s of western Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and the Mediterranean region, from 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...
south to Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...
and Libya
Libya
Libya is an African country in the Maghreb region of North Africa bordered by the Mediterranean Sea to the north, Egypt to the east, Sudan to the southeast, Chad and Niger to the south, and Algeria and Tunisia to the west....
, and east to Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
.
Description
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
by 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...
, 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...
or perennial plant
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...
growing to 0.5–2 m (rarely 3 m) tall. 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 orbicular, 8–18 cm diameter, palmately lobed with five to nine lobes, and a coarsely serrated margin. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are 3–4 cm diameter, dark pink to purple and grow in fasciculate axillary clusters of two to seven. It grows mainly on exposed coastal locations, often on small island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
s, only rarely any distance inland.
Although long considered a species of Lavatera
Lavatera
Lavatera is a genus of about 25 species of flowering plants in the family Malvaceae, native to the Mediterranean region, central and eastern Asia, and Australia. A number of species previously listed in this genus have now been transferred to the related genus Malva...
, genetic and morphological analysis by Martin Forbes Ray, reported in 1998, suggested it was better placed in the genus Malva
Malva
Malva is a genus of about 25–30 species of herbaceous annual, biennial, and perennial plants in the family Malvaceae , one of several closely related genera in the family to bear the common English name mallow. The genus is widespread throughout the temperate, subtropical and tropical regions of...
, in which it was named Malva dendromorpha M.F.Ray. However the earlier name Malva arborea L. (Webb & Berthol.) was validly published and has priority over Malva dendromorpha.
Habitat
Lavatera arborea tolerates sea water to varying degrees, at up to 100% sea water in its natural habitat, excreting salt through glands on its leaves. This salt tolerance can be a competitive advantage over inland plant species in coastal areas. Its level of salinitySalinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
tolerance is thought to be improved by soil with higher phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
content, making guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
enrichment particularly beneficial.
Uses
The leaves of the species are used in herbal medicine to treat sprains, by steeping them in hot water and applying the poulticePoultice
A poultice, also called cataplasm, is a soft moist mass, often heated and medicated, that is spread on cloth over the skin to treat an aching, inflamed, or painful part of the body. It can be used on wounds such as cuts...
to the affected area. It is theorised that lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....
keepers may have spread the plant to some British islands for use as a poultice and to treat burns, an occupational hazard.
Thought to have been used as an alternative to toilet paper. The seeds are edible and are known in Jersey as "petit pains", or "little breads".
Tree Mallow was considered a nutritive animal food in Britain in the 19th century, and is still sometimes used as animal fodder
Fodder
Fodder or animal feed is any agricultural foodstuff used specifically to feed domesticated livestock such as cattle, goats, sheep, horses, chickens and pigs. Most animal feed is from plants but some is of animal origin...
in Europe.
Lavatera arborea has long been cultivated in British gardens, as described in the 1835 self-published book British Phaenogamous Botany, which used the then-common name Sea Tree-mallow: "This species is frequently met with in gardens, where, if it is allowed to scatter its seeds, it will spring up for many successive years, and often attain a large size. The young plants will, as Sir J. E. Smith observes, now and then survive one or more mild Winters; but having once blossomed it perishes."
While sometimes detrimental to seabird habitat, management of Tree Mallow (both planting and thinning) has been successfully employed to shelter nesting sites of the threatened Roseate Tern
Roseate Tern
The Roseate Tern is a seabird of the tern family Sternidae. This bird has a number of geographical races, differing mainly in bill colour and minor plumage details....
, which requires more coverage than Common Tern
Common Tern
The Common Tern is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding in temperate and sub-Arctic regions of Europe, Asia and east and central North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. It is sometimes...
s to impede predation.
Invasive spread
Tree Mallow seeds may be transported between separated coastal areas by the floating fruit, and seabirds are considered a likely means of spread. The seeds are encased in an impermeable outer case, and can remain viable for years, even after extended immersion in saltwater.The Tree Mallow's recent increased range among Scottish islands has raised concerns that it is displacing native vegetation, and is reducing Atlantic Puffin
Atlantic Puffin
The Atlantic Puffin is a seabird species in the auk family. It is a pelagic bird that feeds primarily by diving for fish, but also eats other sea creatures, such as squid and crustaceans. Its most obvious characteristic during the breeding season is its brightly coloured bill...
(Fratercula arctica) populations in affected areas. The plant forms dense stands along the island coasts that inhibit breeding, and causes the puffins to abandon their burrows.
Its spread among Australian islands in recent decades is thought to be reducing biodiversity, soil retention, and seabird habitat. According to one study, "Crested and Caspian Terns that nest in the open are closed out by the canopy, and Little Penguins (Eudyptula minor) and Bridled Terns (Sterna anaethetus) are excluded by the lack of undergrowth".