Flora of the Cocos (Keeling) Islands

The vascular plant flora of the Cocos (Keeling) Islands consists of approximately 61 species native to the 22 vegetated islands and about 69 introduced species, most of which are confined to the two larger inhabited islands, Home Island and West Island. There are no plant species endemic to the islands; however, one variety of Pandanus tectorius is only found growing on these islands. The native vegetation of the two atolls primarily consists of sea-dispersed shoreline plants of the Indo-Pacific region. On the lagoon shoreline, tall shrublands are dominated by Pemphis acidula and Cordia subcordata, often growing in monospecific stands. Closed forest stands are dominated by either Cocos nucifera or Pisonia grandis.[1]

North Keeling, a national park

Much of the area of the southern islands has been modified for coconut plantations, altering the vegetation from the pre-settlement era. North Keeling, about 25 kilometres (16 mi) to the north, has been protected as part of the Pulu Keeling National Park, where 31 plants can be found, of which six are introduced. About half of the species on the southern atoll are introduced.[1][2]

In a report to Parks Australia in 2002, of the many introduced species on the southern atoll, Chromolaena odorata (Siam weed) was identified as being the greatest threat to the environment.[2] Most of the introduced species are pantropical herbaceous plants likely introduced to the southern atoll after the airfield was built in 1944.[1]

History

The Cocos (Keeling) Islands are isolated, being the only atolls in the eastern Indian Ocean, and were uninhabited until relatively recently in the early 19th century. The first botanical study was done while naturalist Charles Darwin visited the southern atoll for ten days, arriving April 1, 1836. Darwin collected 21 species during his time on the islands.[1]

In such a loose, dry, stony soil, nothing but the climate of the intertropical regions could produce a vigorous vegetation. Besides the Cocoa nut which is so numerous as at first to appear the only tree, there are five or six other kinds. One called the Cabbage tree, grows to a great bulk in proportion to its height, & has an irregular figure; its wood being very soft. Besides these trees the number of native plants is exceedingly limited; I suppose it does not exceed a dozen. Yet the woods, from the dead branches of the trees, & the arms of the Cocoa nuts is a thick jungle.

Charles Darwin, HMS Beagle diary[3]

Later, the Scottish botanist Henry Ogg Forbes botanised the southern islands in 1879, collecting 38 species in 22 days, followed by W. E. Birch in 1885 and the British botanist Henry B. Guppy, who spent ten weeks in 1888 on both atolls. By far the longest visit by a naturalist was that of Frederic Wood Jones who spent 15 months on the southern atoll in 1909 and published his account in the book, Coral and Atolls. A History and Description of the Keeling-Cocos Islands, with an account of their Fauna and Flora, and a Discussion of the Method of Development and Transformation of Coral Structures in General, published in 1912. The northern atoll was visited in 1941 by the British naturalist Carl Alexander Gibson-Hill, who provided the first systematic assessment of the plant communities and a description of the dominant flora. The 1980s saw the two largest surveys in 1985 by I. R. Telford, who collected 93 species from both atolls, and in 1986-1987 by D. G. Williams, who collected 130 from all islands.[1]

Species

SpeciesFamilyVernacular nameLocal nameStatusImage
Dicliptera ciliataAcanthaceaenative
Sesuvium portulacastrumAizoaceaesea purslanenative
Achyranthes aspera var. villosiorAmaranthaceaechaff flowernative
Aerva lanataAmaranthaceaeintroduced
Crinum asiaticumAmaryllidaceaecrinum lilynative
Zephyranthes roseaAmaryllidaceaeintroduced
Ochrosia oppositifoliaApocynaceaeKayu Lakinative
Cocos nuciferaArecaceaecoconutKelapanative
Austroeupatorium inulaefoliumAsteraceaestinkweedintroduced
Chromolaena odorataAsteraceaeSiam weedintroduced
Cyanthillium cinereumAsteraceaeintroduced
Eleutheranthera ruderalisAsteraceaeintroduced
Emilia sonchifoliaAsteraceaeintroduced
Erigeron bonariensisAsteraceaefleabaneintroduced
Melanthera bifloraAsteraceaebeach sunflowernative
Sonchus oleraceusAsteraceaemilk thistleintroduced
Synedrella nodifloraAsteraceaeintroduced
Tridax procumbensAsteraceaeintroduced
Argusia argenteaBoraginaceaeoctopus bushKayu Sirehnative
Cordia subcordataBoraginaceaesea trumpetGeronggangnative
Lepidium virginicumBrassicaceaeintroduced
Caesalpinia bonducCaesalpiniaceaenickernutKelenchinative
Senna occidentalisCaesalpiniaceaeintroduced
Calophyllum inophyllumCalophyllaceaeAlexandrian laurelNyamplongnative
Hippobroma longifloraCampanulaceaeintroduced
Carica papayaCaricaceaepawpawKatisintroduced
Casuarina equisetifolia subsp. equisetifoliaCasuarinaceaecoastal sheoakCemaranative
Cleome gynandraCleomaceaenative
Terminalia catappaCombretaceaesea almondKetapangnative
Tradescantia spathaceaCommelinaceaeintroduced
Ipomoea violaceaConvolvulaceaemoon flowernative
Ipomoea pes-capraeConvolvulaceaegoat's-footKangkong Meryapnative
Bryophyllum pinnatumCrassulaceaeintroduced
Syringodium isoetifoliumCymodoceaceaesea grassnative
Thalassodendron ciliatumCymodoceaceaesea grassnative
Cyperus bulbosusCyperaceaenut grassnative
Cyperus javanicusCyperaceaenative
Cyperus polystachyosCyperaceaeintroduced
Fimbristylis cymosaCyperaceaenative
Queenslandiella hyalinaCyperaceaenative
Acalypha indicaEuphorbiaceaenative
Acalypha lanceolataEuphorbiaceaenative
Euphorbia atotoEuphorbiaceaenative
Euphorbia cyathophoraEuphorbiaceaedwarf poinsettiaintroduced
Euphorbia hirtaEuphorbiaceaeintroduced
Euphorbia prostrataEuphorbiaceaeintroduced
Ricinus communisEuphorbiaceaecastor oil plantPokok Jaru Jarakintroduced
Alysicarpus vaginalisFabaceaeintroduced
Canavalia catharticaFabaceaesea beannative
Crotalaria retusaFabaceaeintroduced
Desmodium triflorumFabaceaeintroduced
Erythrina variegataFabaceaecoral treeKayu Dedapnative
Indigofera hirsutaFabaceaeintroduced
Leucaena leucocephalaFabaceaeleucaenaPetehintroduced
Macroptilium atropurpureumFabaceaesiratrointroduced
Sesbania cannabinaFabaceaeintroduced
Sesbania grandifloraFabaceaeTuriintroduced
Vigna marinaFabaceaenative
Enicostema axillare subsp. littoraleGentianaceaenative
Scaevola taccadaGoodeniaceaesea lettuceKayu Kankongnative
Hernandia nymphaeifoliaHernandiaceaesea hearseKayu Jambu Hutannative
Thalassia hemprichiiHydrocharitaceaesea grassnative
Clerodendrum indicumLamiaceaeintroduced
Vitex trifoliaLamiaceaenative
Volkameria inermisLamiaceaesorcerer's flowernative
Cassytha filiformisLauraceaedevil's twinenative
Barringtonia asiaticaLecythidaceaebox fruitKayu Besaginative
Pemphis acidulaLythraceaeKayu Keritingnative
Hibiscus tiliaceusMalvaceaecotton treePokok Warunative
Sida acutaMalvaceaeintroduced
Thespesia populneaMalvaceaeportia treeWaru Hutannative
Triumfetta repensMalvaceaeBingit burrnative
Muntingia calaburaMuntingiaceaeBuah Cheriintroduced
Eugenia sp.MyrtaceaeJambu Ayerintroduced
Psidium guajavaMyrtaceaeguavaJambu Bijiintroduced
Boerhavia albifloraNyctaginaceaeintroduced
Boerhavia diffusaNyctaginaceaeintroduced
Boerhavia repensNyctaginaceaenative
Pisonia grandisNyctaginaceaepisoniaAmpolnative
Ximenia americanaOlacaceaeyellow plumRukamnative
Striga angustifoliaOrobanchaceaeintroduced
Pandanus tectorius var. cocosensisPandanaceaescrew palmPandannative
Passiflora foetida var. hispidaPassifloraceaestinking passionflowerintroduced
Turnera ulmifoliaPassifloraceaeintroduced
Breynia distichaPhyllanthaceaeintroduced
Phyllanthus amarusPhyllanthaceaenative
Sauropus androgynusPhyllanthaceaeKeretuintroduced
Rivina humilisPhytolaccaceaecoral berryintroduced
Scoparia dulcisPlantaginaceaeintroduced
Apluda muticaPoaceaeintroduced
Bothriochloa bladhiiPoaceaeintroduced
Brachiaria brizanthaPoaceaeintroduced
Cenchrus ciliarisPoaceaeintroduced
Cenchrus echinatusPoaceaesand burrintroduced
Chloris barbataPoaceaeintroduced
Chrysopogon aciculatusPoaceaeintroduced
Cynodon dactylonPoaceaecouch grassintroduced
Cynodon radiatusPoaceaeintroduced
Dactyloctenium aegyptiumPoaceaeintroduced
Desmostachya bipinnataPoaceaeintroduced
Digitaria setigeraPoaceaeintroduced
Eleusine indicaPoaceaecrowsfoot grassintroduced
Eragrostis amabilisPoaceaeintroduced
Eriochloa meyerianaPoaceaeintroduced
Imperata cylindrica var. majorPoaceaebladey grassintroduced
Ischaemum muticumPoaceaeintroduced
Lepturopetium sp. aff. marshallensePoaceaenative
Lepturus repensPoaceaestalky grassnative
Panicum repensPoaceaeintroduced
Paspalum vaginatumPoaceaenative
Sporobolus fertilisPoaceaesand couch grassintroduced
Stenotaphrum micranthumPoaceaebeach buffalo grassnative
Thuarea involutaPoaceaebird's-beak grassnative
Zoysia matrellaPoaceaenative
Unidentified sp.Poaceaeintroduced
Portulaca oleraceaPortulacaceaepigweednative
Rhizophora apiculataRhizophoraceaespider mangrovenative
Guettarda speciosaRubiaceaeKembang Melati Hutannative
Morinda citrifoliaRubiaceaecheesefruitMengkudunative
Oldenlandia corymbosaRubiaceaeintroduced
Spermacoce remotaRubiaceaeintroduced
Triphasia trifoliaRutaceaeBuah Kengkitintroduced
Allophylus cobbeSapindaceaenative
Dodonaea viscosaSapindaceaehopbushnative
Physalis minimaSolanaceaeChepelokintroduced
Solanum americanumSolanaceaeblackberry nightshadeintroduced
Suriana maritimaSurianaceaenative
Laportea aestuansUrticaceaenative
Phyla nodifloraVerbenaceaeintroduced
Premna serratifoliaVerbenaceaenative
Stachytarpheta jamaicensisVerbenaceaeblue snakeweedintroduced

See also

References

  1. Williams, D.G. 1994. Vegetation and flora of the Cocos (Keeling) Islands. Atoll Research Bulletin, 404: 1-29.
  2. Claussen, J., and D. Slip. 2002. The status of exotic plants on the Cocos (Keeling) Islands, Indian Ocean. Parks Australia North, Department of the Environment. Accessed online: 13 May 2015.
  3. Keynes, Richard. 2001. Charles Darwin's Beagle Diary. Cambridge University Press. pp. 414–415.
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