Flora of the Cocos (Keeling) Islands

North Keeling, a national park

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 dominted by either Cocos nucifera or Pisonia grandis.[1]

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 about six are introduced or naturalised. 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

Species Family Vernacular name Local name Status Image
Dicliptera ciliata Acanthaceae native
Sesuvium portulacastrum Aizoaceae sea purslane native
Achyranthes aspera var. villosior Amaranthaceae chaff flower native
Aerva lanata Amaranthaceae introduced
Crinum asiaticum Amaryllidaceae crinum lily native
Zephyranthes rosea Amaryllidaceae introduced
Ochrosia oppositifolia Apocynaceae Kayu Laki native
Cocos nucifera Arecaceae coconut Kelapa native
Austroeupatorium inulaefolium Asteraceae stinkweed introduced
Chromolaena odorata Asteraceae Siam weed introduced
Cyanthillium cinereum Asteraceae introduced
Eleutheranthera ruderalis Asteraceae introduced
Emilia sonchifolia Asteraceae introduced
Erigeron bonariensis Asteraceae fleabane introduced
Melanthera biflora Asteraceae beach sunflower native
Sonchus oleraceus Asteraceae milk thistle introduced
Synedrella nodiflora Asteraceae introduced
Tridax procumbens Asteraceae introduced
Argusia argentea Boraginaceae octopus bush Kayu Sireh native
Cordia subcordata Boraginaceae sea trumpet Geronggang native
Lepidium virginicum Brassicaceae introduced
Caesalpinia bonduc Caesalpiniaceae nickernut Kelenchi native
Senna occidentalis Caesalpiniaceae introduced
Calophyllum inophyllum Calophyllaceae Alexandrian laurel Nyamplong native
Hippobroma longiflora Campanulaceae introduced
Carica papaya Caricaceae pawpaw Katis introduced
Casuarina equisetifolia subsp. equisetifolia Casuarinaceae coastal sheoak Cemara native
Cleome gynandra Cleomaceae native
Terminalia catappa Combretaceae sea almond Ketapang native
Tradescantia spathacea Commelinaceae introduced
Ipomoea violacea Convolvulaceae moon flower native
Ipomoea pes-caprae Convolvulaceae goat's-foot Kangkong Meryap native
Bryophyllum pinnatum Crassulaceae introduced
Syringodium isoetifolium Cymodoceaceae sea grass native
Thalassodendron ciliatum Cymodoceaceae sea grass native
Cyperus bulbosus Cyperaceae nut grass native
Cyperus javanicus Cyperaceae native
Cyperus polystachyos Cyperaceae introduced
Fimbristylis cymosa Cyperaceae native
Queenslandiella hyalina Cyperaceae native
Acalypha indica Euphorbiaceae native
Acalypha lanceolata Euphorbiaceae native
Euphorbia atoto Euphorbiaceae native
Euphorbia cyathophora Euphorbiaceae dwarf poinsettia introduced
Euphorbia hirta Euphorbiaceae introduced
Euphorbia prostrata Euphorbiaceae introduced
Ricinus communis Euphorbiaceae castor oil plant Pokok Jaru Jarak introduced
Alysicarpus vaginalis Fabaceae introduced
Canavalia cathartica Fabaceae sea bean native
Crotalaria retusa Fabaceae introduced
Desmodium triflorum Fabaceae introduced
Erythrina variegata Fabaceae coral tree Kayu Dedap native
Indigofera hirsuta Fabaceae introduced
Leucaena leucocephala Fabaceae leucaena Peteh introduced
Macroptilium atropurpureum Fabaceae siratro introduced
Sesbania cannabina Fabaceae introduced
Sesbania grandiflora Fabaceae Turi introduced
Vigna marina Fabaceae native
Enicostema axillare subsp. littorale Gentianaceae native
Scaevola taccada Goodeniaceae sea lettuce Kayu Kankong native
Hernandia nymphaeifolia Hernandiaceae sea hearse Kayu Jambu Hutan native
Thalassia hemprichii Hydrocharitaceae sea grass native
Clerodendrum indicum Lamiaceae introduced
Vitex trifolia Lamiaceae native
Volkameria inermis Lamiaceae sorcerer's flower native
Cassytha filiformis Lauraceae devil's twine native
Barringtonia asiatica Lecythidaceae box fruit Kayu Besagi native
Pemphis acidula Lythraceae Kayu Keriting native
Hibiscus tiliaceus Malvaceae cotton tree Pokok Waru native
Sida acuta Malvaceae introduced
Thespesia populnea Malvaceae portia tree Waru Hutan native
Triumfetta repens Malvaceae Bingit burr native
Muntingia calabura Muntingiaceae Buah Cheri introduced
Eugenia sp. Myrtaceae Jambu Ayer introduced
Psidium guajava Myrtaceae guava Jambu Biji introduced
Boerhavia albiflora Nyctaginaceae introduced
Boerhavia diffusa Nyctaginaceae introduced
Boerhavia repens Nyctaginaceae native
Pisonia grandis Nyctaginaceae pisonia Ampol native
Ximenia americana Olacaceae yellow plum Rukam native
Striga angustifolia Orobanchaceae introduced
Pandanus tectorius var. cocosensis Pandanaceae screw palm Pandan native
Passiflora foetida var. hispida Passifloraceae stinking passionflower introduced
Turnera ulmifolia Passifloraceae introduced
Breynia disticha Phyllanthaceae introduced
Phyllanthus amarus Phyllanthaceae native
Sauropus androgynus Phyllanthaceae Keretu introduced
Rivina humilis Phytolaccaceae coral berry introduced
Scoparia dulcis Plantaginaceae introduced
Apluda mutica Poaceae introduced
Bothriochloa bladhii Poaceae introduced
Brachiaria brizantha Poaceae introduced
Cenchrus ciliaris Poaceae introduced
Cenchrus echinatus Poaceae sand burr introduced
Chloris barbata Poaceae introduced
Chrysopogon aciculatus Poaceae introduced
Cynodon dactylon Poaceae couch grass introduced
Cynodon radiatus Poaceae introduced
Dactyloctenium aegyptium Poaceae introduced
Desmostachya bipinnata Poaceae introduced
Digitaria setigera Poaceae introduced
Eleusine indica Poaceae crowsfoot grass introduced
Eragrostis amabilis Poaceae introduced
Eriochloa meyeriana Poaceae introduced
Imperata cylindrica var. major Poaceae bladey grass introduced
Ischaemum muticum Poaceae introduced
Lepturopetium sp. aff. marshallense Poaceae native
Lepturus repens Poaceae stalky grass native
Panicum repens Poaceae introduced
Paspalum vaginatum Poaceae native
Sporobolus fertilis Poaceae sand couch grass introduced
Stenotaphrum micranthum Poaceae beach buffalo grass native
Thuarea involuta Poaceae bird's-beak grass native
Zoysia matrella Poaceae native
Unidentified sp. Poaceae introduced
Portulaca oleracea Portulacaceae pigweed native
Rhizophora apiculata Rhizophoraceae spider mangrove native
Guettarda speciosa Rubiaceae Kembang Melati Hutan native
Morinda citrifolia Rubiaceae cheesefruit Mengkudu native
Oldenlandia corymbosa Rubiaceae introduced
Spermacoce remota Rubiaceae introduced
Triphasia trifolia Rutaceae Buah Kengkit introduced
Allophylus cobbe Sapindaceae native
Dodonaea viscosa Sapindaceae hopbush native
Physalis minima Solanaceae Chepelok introduced
Solanum americanum Solanaceae blackberry nightshade introduced
Suriana maritima Surianaceae native
Laportea aestuans Urticaceae native
Phyla nodiflora Verbenaceae introduced
Premna serratifolia Verbenaceae native
Stachytarpheta jamaicensis Verbenaceae blue snakeweed introduced

See also

References

  1. 1 2 3 4 5 Williams, D.G. 1994. Vegetation and flora of the Cocos (Keeling) Islands. Atoll Research Bulletin, 404: 1-29.
  2. 1 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.

External links

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