Malva arborea (previously known as Lavatera arborea, or, more recently as Malva eriocalyx), the tree mallow, is a species of mallow native to the coasts of western Europe and the Mediterranean region, from Ireland and Britain south to Algeria and Libya, and east to Greece.
Description
Flower
It is a shrubby 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 flowers are 3–4 cm diameter, dark pink to purple and grow in fasciculate axillary clusters of two to seven.
Taxonomy
It was first named in 1753 by Carl Linnaeus as Lavatera arborea, but was transferred to the genus Malva in 1836 by Philip Barker-Webb and Sabin Berthelot.
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 & Berthel. was validly published and has priority over Malva dendromorpha.
Habitat
Malva 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 salinity tolerance is thought to be improved by soil with higher phosphate content, making guano enrichment particularly beneficial. It grows mainly on exposed coastal locations, often on small islands, only rarely any distance inland.
