Wiliwili (''Erythrina sandwicensis''), is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of tree in the pea family, Fabaceae, that is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

. It is the only species of '' Erythrina'' that naturally occurs there. It is typically found in

Hawaiian tropical dry forests The Hawaiian tropical dry forests are a tropical dry broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of on the leeward side of the main islands and the summits of Niihau and Kahoolawe. These forests are either seasona ...

on leeward island slopes up to an elevation of . ''Wiliwili'' means "repeatedly twisted" in the Hawaiian language and refers to the seedpods, which

dehisce Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...

, or twist open, to reveal the seeds.

Description

''Wiliwili'' trees grow to a height of with a gnarled and stout trunk that reaches in diameter. The bark is smooth, slightly fissured, and covered in gray or black spines up to in length. The bark on the main trunk of mature trees has a distinct orange cast, which is caused by a terrestrial

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

. The ''wiliwili'' is summer (

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The te ...

)

drought deciduous Drought deciduous, or drought semi-deciduous plants refers to plants that shed their leaves during periods of drought or in the dry season. This phenomenon is a natural process of plants and is caused due to the limitation of water around the env ...

. The dry season usually begins in late April or in May, and trees in the wild typically lose all of their leaves before they bloom. Trees in cultivation may retain much of their foliage through blooming time.George W. Staples and Derral R. Herbst. 2005. "A Tropical Garden Flora" Bishop Museum Press: Honolulu, HI, USA. The flowers appear in the first half of the dry season, from April through July. They form on horizontal or nearly horizontal racemes that are long. The flower color may be orange, yellow, salmon, greenish or whitish. Sometimes all of these colors occur in a single population. The

standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object th ...

petal is erect, not enclosing the other petals. Like all of the erythrinas, the wiliwili is

pollinated Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s.Anne Bruneau. 1996. "Phylogenetic and Biogeographical Patterns in ''Erythrina'' (Leguminosae: Phaseoleae) as Inferred from Morphological and Chloroplast DNA Characters". ''Systematic Botany'' 21(4):587-605. The horizontal raceme and the erect standard are adaptations to pollination by

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by t ...

birds.Anne Bruneau. 1997. "Evolution and Homology of Bird Pollination Syndromes in ''Erythrina'' (Leguminosae). ''American Journal of Botany'' 84(1):54-71. Many other erythrinas are pollinated by hummingbirds, which do not occur in Hawaii. Pods develop and persist on the tree, with the seeds remaining attached long after the pods have opened. The seeds are dislodged by heavy downpours that generally start around November in the islands. Many seeds

germinate Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

quickly, and a well-established seedling can grow to in height before the start of the next dry season. That the ''wiliwili'' bears spines is unusual for a species that has

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

in the isolated Hawaiian Islands, without the presence of

ungulate Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, ...

s or other large

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

s. Many plants in the islands have consequently evolved away the protection of spines. The ''wiliwili'' is thought to be closely related to ''E. tahitensis'', a tree endemic to the Tahitian Archipelago, and ''E. velutina'', a widespread species found in tropical

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 ...

and the Caribbean.

Distribution

Wiliwili is occasionally seen in cultivation in Hawaii. It is easily propagated from cuttings.Otto Degener. 1932. ''Flora Hawaiiensis'' book 5, family 169. (no page numbers). Seven other species of '' Erythrina'' were under general cultivation in the Hawaiian Islands, but have been mostly extirpated by the alien gall wasp (see Conservation, below). They were popular street trees in dry areas and windbreaks on fields. At least 80 others have been known in

botanical garden A botanical garden or botanic gardenThe terms ''botanic'' and ''botanical'' and ''garden'' or ''gardens'' are used more-or-less interchangeably, although the word ''botanic'' is generally reserved for the earlier, more traditional gardens, an ...

s there.Clyde T. Imada, George W. Staples, and Derral R. Herbst. undated. ''Erythrina'' At: "Annotated Checklist of Cultivated Plants of Hawaii" At: Botany Databases At: Hawaii Biological Survey (see ''External links'' below.) No non-native species of ''Erythrina'' is known to be naturalized in Hawaii.Warren L. Wagner, Derral R. Herbst, and Sy H. Sohmer. ''Manual of the Flowering Plants of Hawaii'', Revised Edition, 1999. Bishop Museum Press: Hololulu The ''wiliwili'' is distinguished from the other seven cultivated species by a pod with only one to three red or yellow-orange

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s, which sink in water; non-native ''Erythrina'' have pods with larger numbers of brown seeds, which float in water.

Uses

Native Hawaiians made a number of items from ''wiliwili'' wood because of its low density, such as ''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), '' ama'' (

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 ...

floats, and extremely long ''papa hee nalu'' ( surfboards) called ''olo''. ''Olo'', which averaged , were exclusively ridden by '' alii'' (royalty). The wood was sometimes used for the '' waa'' (hull) of outrigger canoes intended to be used near-shore, for recreation, or for training. The shiny orange-red

s were strung into '' lei''.

Conservation

Like other

indigenous Indigenous may refer to: *Indigenous peoples *Indigenous (ecology), presence in a region as the result of only natural processes, with no human intervention *Indigenous (band), an American blues-rock band *Indigenous (horse), a Hong Kong racehorse ...

species in Hawaii, the wiliwili is threatened by

competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indiv ...

with non-native species that are free of the

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s, and

s that constrain them in their original

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s. It was additionally reported in December 2005 that the Hawaiian ''wiliwili'' population was under immediate threat due to an infestation by a

gall wasp Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this gener ...

, '' Quadrastichus erythrinae'', which had been first reported in Hawaii in April of that year. This invasive species appears to have arrived in Hawaii via southern

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...

and southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

within only two years. This species was not previously known to science and was formally named and described in 2004.I.K. Kim, G. Delvare, and J. La Salle. 2004. "A new species of ''Quadrastichus'' (Hymenoptera: Eulophidae): A gall-inducing pest on ''Erythrina'' (Fabaceae)". ''Journal of Hymenoptera Research'' 13:243-249. It is thought to have originated in Africa, and the means of its rapid dispersal across

South Asia South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;;;;; ...

, the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

, and southern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

is not understood.Daniel Rubinoff, Brenden S. Holland, Alexandra Shibata, Russell H. Messing, and Mark G. Wright. 2010. "Rapid Invasion Despite Lack of Genetic Variation in the Erythrina Gall Wasp (Quadrastichus erythrinae Kim)" ''Pacific Science'' 64(1):23-31. The majority of trees of introduced ''Erythrina'' species have died as a result of gall wasp infestation. Native ''wiliwili'' forests have also been hard hit, particularly Puu o Kali on the island of Maui - prior to 2001, the best remaining example of a

Hawai'i 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 ...

low elevation dryland forest ecosystem. The USGS-Pacific Island Ecosystems Research Center study site now documents the destructive impact of two invasive insect species (African bruchid beetle ''Specularius impressithorax'' and erythrina gall wasp) on Erythrina sandwicensis. A parasitoid second wasp, ''

Eurytoma ''Eurytoma'' is a genus of parasitoid chalcid wasps in the family Eurytomidae The Eurytomidae are a family within the superfamily Chalcidoidea. Unlike most chalcidoids, the larvae of many are phytophagous (feeding in stems, seeds, or galls) ...

erythrinae,'' was released by the Hawaii Department of Agriculture in December 2008 as a

biocontrol Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also in ...

to minimize the damaging effects of ''Quadrastichus''. ''Eurytoma'' wasps lay their eggs in the galls created by ''Quadrastichus'' wasps. ''Eurytoma'' larvae hatch faster than ''Quadrastichus'' larvae, on which they exclusively feed. The introduction of ''Eurytoma'' has reduced the population of ''Quadrastichus'' to a point where the wiliwili trees no longer die, but still have a much reduced production of viable seeds. That's largely because ''Eurytoma'' larvae need to feed on multiple ''Quadrastichus'' to complete their development, and therefore ignore small isolated galls containing a single larva. The Hawaii Departments of Agriculture and of Land & Natural Resources therefore plan to introduce a second parasitoid wasp from Africa, ''

Aprostocetus ''Aprostocetus'' is a genus of hymenopteran insects of the family Eulophidae. The genus was erected by John O. Westwood in 1833. This very large group (about 800 described species) of parasitoid wasps has a global distribution. Species Widespr ...

nitens''. The smaller ''A. nityens'' completes its development feeding from a single ''Quadrastichus'' larva, and it is therefore expected to complement ''Eurytoma'' by targeting isolated larvae.

History

The genus ''Erythrina'' was established by

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1753 in his book, '' Species Plantarum''.Carolus Linnaeus. 1753. ''Species Plantarum'' 2:706. Laurentii Salvii. (see ''External Links'' below). The name means "red", a reference to the flower color of some of the well-known species. In 1786, in his book '' Encyclopédie Méthodique: Botanique'',

Jean-Baptiste Lamarck Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), often known simply as Lamarck (; ), was a French naturalist, biologist, academic, and soldier. He was an early proponent of the idea that biolo ...

originated the name ''Erythrina monosperma'' for a

Leguminous A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock for ...

tree from

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

and

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 ...

.Jean-Baptiste Lamarck. 1786. ''Encyclopédie Méthodique: Botanique'' 2(1):391-392. In: Encyclopédie Méthodique par ordre de matieres. (see ''External links'' below). That tree has been known as ''Butea monosperma'' ever since

William Roxburgh William Roxburgh FRSE FRCPE FLS (3/29 June 1751 – 18 February 1815) was a Scottish surgeon and botanist who worked extensively in India, describing species and working on economic botany. He is known as the founding father of Indian botany. ...

created the genus ''Butea'' in 1795. Unaware of Lamarck's name,

Charles Gaudichaud-Beaupré Charles Gaudichaud-Beaupré (September 4, 1789 – January 16, 1854) was a French botanist. Biography Gaudichaud was born in Angoulême, to J-J. Gaudichaud and Rose (Mallat) Gaudichaud. He studied pharmacology informally at Cognac and Angoulême, ...

created the name ''Erythrina monosperma'' for the Hawaiian ''Erythrina'' in 1830 in his book ''Voyage of the Uranus''.Charles Gaudichaud-Beaupré. 1830. ''Voyage de l'Uranie. Botanique'' (full title: ''Voyage autour du Monde, entrepris par Ordre du Roi, . . . Execute sur les Corvettes de S.M. l'Uranie et la Physicienne . . . par M. Louis de Freycinet. Botanique . . .'') page 486 and table 114. In 1841, William Jackson Hooker and George Arnott used Gaudichaud's name in their book, ''The Botany of Captain Beechey's Voyage''.William Jackson Hooker and George Arnott Walker-Arnott. 1841. ''The Botany of Captain Beechey's Voyage'' part 2, page 81. (see ''External links'' below). Gaudichaud's name, ''Erythrina monosperma'', was used by most of those who described the Hawaiian species of ''Erythrina'' throughout the nineteenth century, including

William Hillebrand Wilhelm or William Hillebrand (November 13, 1821 – July 13, 1886) was a German physician. He practiced medicine in several different countries, including for over 20 years in the Hawaiian islands. In 1850, Hillebrand lived at what is now Fost ...

.William Hillebrand. 1888. Flora of the Hawaiian Islands: ···:99. (reprinted by Lubrecht & Cramer in 1981). (see ''External links'' below.) In 1932,

Otto Degener Otto Degener (May 13, 1899 – January 16, 1988) was a botanist and conservationist who specialized in identifying plants of the Hawaiian Islands. Biography Degener was born May 13, 1899 in East Orange, New Jersey. Degener graduated from the Massa ...

created the name ''Erythrina sandwicensis'' to replace ''Erythrina monosperma''. He stated no reason for the name change. He presented a more complete

synonymy A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

than the one given here. ''Erythrina sandwicensis'' is the name that has been used since 1932.

Wiliwili hula chant

: Auwe! Pau au i ka manō nui, e! : Lala-kea niho pa-kolu. : Pau ka papa-ku o Lono. : O ka ai ia e ka manō nui, : O Niuhi maka ahi, : Olapa i ke kai lipo. : Ahu e! au-we! : A pua ka wiliwili, : A nanahu ka manō : Auwe! pau ai i ka mano nui! : Kai uli, kai ele, : Kai popolohua o Kane. : A lealea au i kau hula, : Pau au i ka manō nui! : Alas! I am seized by the shark, great shark! : Lala-kea with triple-banked teeth. : The stratum of

Lono In Hawaiian religion, the god Lono is associated with fertility, agriculture, rainfall, music and peace. In one of the many Hawaiian stories of Lono, he is a fertility and music god who descended to Earth on a rainbow to marry Laka. In agricultu ...

is gone, : Torn up by the monster shark, : Niuhi with fiery eyes, : That flamed in the deep blue sea. : Alas! and alas! : When the flowers of the wiliwili tree, : That is the time when the shark-god bites. : Alas! I am seized by the huge shark! : O blue sea, O dark sea, : Foam-mottled sea of Kane! : What pleasure I took in my dancing! : Alas! now consumed by the monster shark!