''Hibiscus tiliaceus'', commonly known as the sea hibiscus or coast cottonwood, is a species of

flowering A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

in the mallow family,

Malvaceae Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ...

, with a

pantropical A pantropical ("all tropics") distribution is one which covers tropical regions of both hemispheres. Examples of species include caecilians, modern sirenians and the plant genera ''Acacia'' and ''Bacopa''. ''Neotropical'' is a zoogeographic term ...

distribution along coastlines. It has also been introduced to

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. It has been debated whether this species is native or introduced to

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

Names

Common names include sea hibiscus, beach hibiscus, coastal (or coast) hibiscus, coastal (or coast) cottonwood, green cottonwood, native hibiscus, native rosella, cottonwood hibiscus, kurrajong, sea rosemallow and dhigga ( Maldivian). The plant was introduced by

Austronesian peoples The Austronesian peoples, sometimes referred to as Austronesian-speaking peoples, are a large group of peoples in Taiwan, Maritime Southeast Asia, Micronesia, coastal New Guinea, Island Melanesia, Polynesia, and Madagascar that speak Austro ...

that voyaged across Southeast Asia and Oceania as a source of wood and fibre. This is reflected in the names of the plant as spoken in many related languages spoken in those regions including ''balibago'' ( Tagalog), ''malobago'' ( Bikol), ''malabago'' or ''malbago'' ( Cebuano – Southern), ''maribago'' ( Cebuano – Northern), ''lambago'' (Cebuano - Cagayan de Oro), ''waru'' ( Javanese), ''baru'' or ''bebaru'' ( Malay), ''pagu'' ( Chamorro), ''hau'' ( Hawaiian), ''fau'' ( Samoan), ''purau'' ( Tahitian), and vau tree. The specific epithet, ''"tiliaceus"'', refers to its resemblance of the leaves to those of the related '' Tilia'' species.

Distribution and habitat

''Hibiscus tiliaceus'' has a worldwide distribution. In the Old World and

Oceania Oceania (, , ) is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of and a population of around 44.5 million ...

, it is a common

coast The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...

al plant in most of tropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

South Asia South Asia is the southern subregion of Asia, which is defined in both geographical Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth descr ...

(including the

Maldives Maldives (, ; dv, ދިވެހިރާއްޖެ, translit=Dhivehi Raajje, ), officially the Republic of Maldives ( dv, ދިވެހިރާއްޖޭގެ ޖުމްހޫރިއްޔާ, translit=Dhivehi Raajjeyge Jumhooriyyaa, label=none, ), is an archipelag ...

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...

, parts of

East Asia East Asia is the eastern region of Asia, which is defined in both Geography, geographical and culture, ethno-cultural terms. The modern State (polity), states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. ...

(as far north as central Japan, where it reaches its northernmost extent), eastern and northern Australia, and much of the Pacific Islands, including

(where its establishment status is uncertain). It has also been introduced to

. A separate variety, var. ''pernambucensis'' (formerly considered a separate species, ''H. pernambucensis''), is native to the tropical

New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...

, including

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

, the Caribbean, and much of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

. This variety has also been introduced to

. It is uncertain if the species is native to Hawaii, as it may have been introduced by the

Polynesia Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...

ns. It is considered native by Plants of the World Online, but the IUCN considers it of uncertain status. ''Hibiscus tiliaceus'' can be found at elevations from sea level to in areas that receive of annual rainfall. It is commonly found growing on

beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc sh ...

es, by rivers and in

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

swamps. Sea hibiscus is well adapted to grow in coastal environment in that it tolerates

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

and waterlogging and can grow in

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...

coral sand Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secr ...

, marl,

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

, and crushed

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

. It grows best in slightly acidic to alkaline

soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

s ( pH of 5–8.5). Cotton Tree, Queensland, Australia is named for the plant.

Description

''Hibiscus tiliaceus'' reaches a height of , with a trunk up to in diameter. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s of ''H. tiliaceus'' are bright yellow with a deep red center upon opening. Over the course of the day, the flowers deepen to orange and finally red before they fall. The branches of the tree often curve over time. The leaves are heart shaped and deep red in the var. rubra.

Uses

The wood of ''H. tiliaceus'' has a

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...

of 0.6. It has been used in a variety of applications, such as seacraft construction, firewood, and

wood carving Wood carving is a form of woodworking by means of a cutting tool (knife) in one hand or a chisel by two hands or with one hand on a chisel and one hand on a mallet, resulting in a wooden figure or figurine, or in the sculptural ornamentation ...

s. It is easy to plane and turns well, so it is regarded by many as a high quality furniture wood. Plant fibers taken from the stems have traditionally been used in

rope A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similar ...

making, while its bark has been used like cork, in sealing cracks in boats. The bark and roots may be boiled to make a cooling tea to cool

fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...

s, and its young leafy

shoot In botany, a plant shoot consists of any plant stem together with its appendages, leaves and lateral buds, flowering stems, and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the sp ...

s may be eaten as vegetables. Native Hawaiians used the wood to make '' iako'' (spars) for ''waa'' (

outrigger canoe Outrigger boats are various watercraft featuring one or more lateral support floats known as outriggers, which are fastened to one or both sides of the main hull. They can range from small dugout canoes to large plank-built vessels. Outrigger ...

s), ''mouo'' (

fishing net A fishing net is a Net (device), net used for fishing. Nets are devices made from fibers woven in a grid-like structure. Some fishing nets are also called fish traps, for example #Fyke nets, fyke nets. Fishing nets are usually meshes formed by ...

floats), and ''au koi'' (

adze An adze (; alternative spelling: adz) is an ancient and versatile cutting tool similar to an axe but with the cutting edge perpendicular to the handle rather than parallel. Adzes have been used since the Stone Age. They are used for smoothing ...

handles). ''Kaula ilihau'' (cordage) was made from the

bast fiber Bast fibre (also called phloem fibre or skin fibre) is plant fibre collected from the phloem (the "inner bark", sometimes called "skin") or bast surrounding the stem of certain dicotyledonous plants. It supports the conductive cells of the phloe ...

s. ''Hau'' would be used to make '' ama'' (canoe floats) if ''

wiliwili Wiliwili (''Erythrina sandwicensis''), is a species of tree in the pea family, Fabaceae, that is endemic to the Hawaiian Islands. It is the only species of ''Erythrina'' that naturally occurs there. It is typically found in Hawaiian tropical dry ...

'' (''Erythrina sandwicensis'') was unavailable. ''Hibiscus tiliaceus'' is widely used in Asian countries as a subject for the art of bonsai, especially Taiwan. The finest specimens are taken from Kenting National Park. Lending itself to free grafting, the leaf size is reduced fairly quickly. Its leaves are also used in cooking, as trays for steamed rice cakes ( 粿). In

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

''H. tiliaceus'' is also used for fermenting

tempeh Tempeh or tempe (; jv, ꦠꦺꦩ꧀ꦥꦺ, témpé, ) is a traditional Indonesian food made from fermented soybeans. It is made by a natural culturing and controlled fermentation process that binds soybeans into a cake form. A fungus, '' Rhiz ...

. The undersides of the leaves are covered in downy hairs known technically as trichomes to which the mold '' Rhizopus oligosporus'' can be found adhering in the wild. Soybeans are pressed into the leaf, and stored. Fermentation occurs resulting in tempeh.

Chemistry

Cyanidin-3-glucoside is the major anthocyanin found in flowers of ''H. tiliaceus''. Leaves of ''H. tiliaceus'' displayed strong free radical scavenging activity and the highest tyrosinase inhibition activity among 39 tropical plant species in Okinawa. With greater UV radiation in coastal areas, it is possible that leaves and flowers of natural coastal populations of ''H. tiliaceus'' have stronger antioxidant properties than planted inland populations.(Wong ''et al''., 2009; Wong & Chan, 2010).

References

Bibliography

*Masuda, T., Yonemori, S., Oyama, Y., Takeda, Y., Tanaka, T., Andoh, T., Shinohara, A., Nakata, M. (1999). ”Evaluation of the antioxidant activity of environmental plants: activity of the leaf extracts from seashore plants”. ''Journal of Agricultural and Food Chemistry'' 47: 1749–1754. *Masuda, T., Yamashita, D., Takeda, Y., Yonemori, S. (2005). “Screening for tyrosinase inhibitors among extracts of seashore plants and identification of potent inhibitors from ''Garcinia subelliptica''”. ''Bioscience, Biotechnology, and Biochemistry'' 69: 197–201. *Wong, S.K., Lim, Y.Y., Chan, E.W.C. (2009). “Antioxidant properties of ''Hibiscus'': Species variation, altitudinal change, coastal influence and floral colour change”. ''Journal of Tropical Forest Science'' 21(4): 307–315. *Wong, S.K., Chan, E.W.C. (2010). “Antioxidant properties coastal and inland populations of ''Hibiscus tiliaceus''”. ''ISME/GLOMIS Electronic Journal'' 8(1): 1–2. http://www.glomis.com/ej/pdf/EJ_8-1.pdf. {{Taxonbar, from=Q10292396 tiliaceus Flora of Norfolk Island Malvales of Australia Flora of Queensland Flora of the Maldives Trees of Australia Trees of the Philippines Trees of the Pacific Flora of Christmas Island Plants described in 1753 Taxa named by Carl Linnaeus