Wiliwili (''Erythrina sandwicensis'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of tree in the pea family,

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

, that is

endemic Endemism is the state of a species being found only 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 foun ...

to the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

. It is the only species of ''

Erythrina ''Erythrina'' is a genus of plants in the pea family, Fabaceae. It contains about 130 species, which are distributed in tropical and subtropical regions worldwide. They are trees, with the larger species growing up to in height. These species ...

'' that naturally occurs there. It is typically found in

Hawaiian tropical dry forests 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 seasonal or sc ...

leeward In geography and seamanship, windward () and leeward () are directions relative to the wind. Windward is ''upwind'' from the point of reference, i.e., towards the direction from which the wind is coming; leeward is ''downwind'' from the point o ...

island slopes up to an elevation of . ''Wiliwili'' means "repeatedly twisted" in the

Hawaiian language Hawaiian (', ) is a critically endangered Polynesian language of the Austronesian language family, originating in and native to the Hawaiian Islands. It is the native language of the Hawaiian people. Hawaiian, along with English, is an offi ...

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 Bark may refer to: Common meanings * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Arts and entertainment * ''Bark'' (Jefferson Airplane album), ...

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 ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, suc ...

. 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 t ...

)

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

raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...

s 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 ...

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

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. Pollinating agents can be animals such as insects, for example bees, beetles or butterflies; bird ...

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

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 generally have an anisodactyl arrangement of their ...

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

hummingbird Hummingbirds are birds native to the Americas and comprise the Family (biology), biological family Trochilidae. With approximately 366 species and 113 genus, genera, they occur from Alaska to Tierra del Fuego, but most species are found in Cen ...

s, 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 flowering plant, angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the sp ...

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 the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

in the isolated Hawaiian Islands, without the presence of

ungulate Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...

s or other large

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

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 considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

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 ''

'' 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. is ...

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 Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...

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 In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

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

Uses

Native Hawaiians Native Hawaiians (also known as Indigenous Hawaiians, Kānaka Maoli, Aboriginal Hawaiians, or simply Hawaiians; , , , and ) are the Indigenous Polynesian people of the Hawaiian Islands. Hawaiʻi was settled at least 800 years ago by Polynesian ...

made a number of items from ''wiliwili'' wood because of its low density, such as ''mouo'' (

fishing net A fishing net or fish net is a net (device), net used for fishing. Fishing nets work by serving as an improvised fish trap, and some are indeed rigged as traps (e.g. #Fyke nets, fyke nets). They are usually wide open when deployed (e.g. by cast ...

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 (watercraft), hull. They can range from small dugout (boat), dugout canoes to large ...

floats, and extremely long ''papa hee nalu'' (

surfboard A surfboard is a narrow plank used in surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding an ocean wave. They were invented in ancient Hawaii, where they were known as ''papa hee ...

s) 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 many other native 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, indi ...

with non-native species that are free of the

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

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

s, and

s that constrain them in their original

habitat In ecology, habitat refers to the array of resources, 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 manifestation of its ...

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 traditionally 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 gene ...

, ''

Quadrastichus erythrinae ''Quadrastichus erythrinae'' Kim, 2004, (''quadra''=four, ''stichus''=line, ''erythrinae''=of erythrina) is a small parasitoid wasp belonging to the family Eulophidae, but also a secondary phytophage by way of inducing galls on the leaves, stems, ...

'', which had been first reported in Hawaii in April of that year. This

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

appears to have arrived in Hawaii via southern

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

and southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

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#Asia, subregion of Asia that is defined in both geographical and Ethnicity, ethnic-Culture, cultural terms. South Asia, with a population of 2.04 billion, contains a quarter (25%) of the world's populatio ...

, 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 the definition, to Antarctica in the south, and is bounded by the cont ...

, and southern

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

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 Maui (; Hawaiian language, Hawaiian: ) is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the List of islands of the United States by area, 17th-largest in the United States. Maui is one of ...

- prior to 2001, the best remaining example of a

Hawai'i Hawaii ( ; ) is an island state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two non-contiguous U.S. states (along with Alaska), it is the only state not on the North American mainland, th ...

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 In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

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 pest control, controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or phytopathology, plants by bioeffector, using other organisms. It relies o ...

to minimize the damaging effects of ''Quadrastichus''. ''Eurytoma'' wasps lay their eggs in the

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...

s 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 egg-laying female ''Eurytoma'' 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 (biology), 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. ...

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 ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in 1753 in his book, ''

Species Plantarum ' (Latin for "The Species of Plants") is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genus, genera. It is the first work to consistently apply binomial nomenclature ...

''.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 biologi ...

originated the

name A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A person ...

''Erythrina monosperma'' for a

Leguminous Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

tree from

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

.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 Linnean Society of London, FLS (3/29 June 1751 – 18 February 1815) was a Scottish people, Scottish surgeon and botanist who worked extensively in India, describing species and working on economic botany. He is known ...

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 Sir William Jackson Hooker (6 July 178512 August 1865) was an English botany, botanist and botanical illustrator, who became the first director of Kew Gardens, Kew when in 1841 it was recommended to be placed under state ownership as a botan ...

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 Foste ...

.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 Mass ...

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 precisely 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 a ...

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 agricul ...

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!