FLORA OF KIRITIMATI (CHRISTMAS) ATOLL, NORTHERN LINE ISLANDS, REPUBLIC OF KIRIBATI

1 DEDICATION


INTRODUCTION
This paper is a compilation and analysis of all vascular plants that have been reported on Kiritimati (Christmas) Atoll in the Northern Line Islands of the Republic of Kiribati. It is based on field inventories conducted by the authors on six field visits to the atoll between 1996 and 2012 plus available published and unpublished records of vascular plant collections and observations made on the atoll. Most of the earlier published records were reviewed by Wester (1985), along with a compilation of species that he collected and observed during a one-week visit in August 1982 (see Table 2 for the details of previous collectors). R. R. Thaman (RRT) visited the island for two one-week periods in 1996 and 2006, during which he attempted to inventory all vascular plants present on the island, including weeds and cultivated species, and after which he completed a working annotated record of the flora, including local I-Kiribati names and ethnobotanical information. This record was verified, updated and augmented by Alan Tye (AT), based on four visits to the island, totaling five weeks from 2008 to 2012, when he paid particular attention to native and naturalized introduced species. AT also carried out a new review of the Kiritimati literature and examination of Kiritimati specimens at BISH, particularly those representing unique or unusual species records, including those not found by either of us.
We first present relevant background information on the geography, history and physical environment of Kiritimati Atoll, the main terrestrial and nearshore lagoon habitats, the major vegetation types and the terrestrial flora. This is followed by an annotated systematic listing of all vascular plant taxa reported at some time from Kiritimati.

Brief History
This brief account focuses on a few points of history of relevance to the development of the flora of Kiritimati; a more comprehensive historical review has been given by Perry (1981). At the time of European discovery by Hernando de Grijalva's Spanish expedition in 1537, and when Captain James Cook visited the island on 24 December 1777, Kiritimati was uninhabited, although there are remains of early temporary Polynesian settlement (Emory, 1934;Maude, 1968). Although subsequent contact was made with the island after Cook and there was sporadic phosphate mining on the islands after 1858, more or less permanent occupation of the island began in 1882 when large-scale coconut planting began. By 1886 some 18,000-20,000 coconut palms had been planted and 200 tons of pearl shell exploited. By the turn of the century, some 70,000 coconut palms had been planted, although only 25% survived due to prolonged drought (Jenkin and Foale, 1968). Kiritimati was uninhabited from 1905-1912 after which it, along with Washington and Fanning Islands, was run as a coconut plantation by Central Pacific Coconut Plantations Ltd. The Gilbert and Ellice Islands Company took over the management of the Christmas Island coconut plantations in 1941. It has been estimated that coconut plantation has replaced about onethird of the natural vegetation of the island and that the government coconut estate covered some 5,170 ha (Garnett, 1983;Teeb'aki, 1993).
During World War II the island was occupied by Allied troops, who constructed several airstrips, an extensive road network and other infrastructure. From 1956 to 1962, atmospheric nuclear bomb tests were conducted by the British and Americans off the island, during which time up to 4,000 servicemen were Kiritimati based there. Military interest ended in 1969 and, using the remaining infrastructure, including 100 km of sealed road, Kiritimati was established as the administrative center of the Line Islands (Wester, 1985;Teeb'aki, 1993). Since Kiribati independence in 1979, Kiritimati, with its extensive land area, became the focus for resettlement of people from Tarawa and other highly populated atolls of Kiribati. By 1989 the population was estimated at 2,000, most of whom lived in London, Banana and Poland villages in the west of the island (Teeb'aki, 1993). By 2010 the population was estimated to be about 5, 791, compared to 5,115 and 3,431 in 2005and 2000, respectively (Office of Te Beretitenti and T'Makei Affairs, 2012. From the time of coconut plantation development, especially during military occupation and the development of the island as the administrative center and focus for resettlement, a range of exotic ornamentals, food plants and other plants, including weeds, have been deliberately or accidentally introduced to the island. For example, two species of Pluchea became widely dispersed throughout the island soon after World War II and now form dense stands in many areas, especially around the main settlements (Teeb'aki, 1992). There have also been a number of attempts, as part of resettlement efforts, to promote home food production and household vegetable gardening, and the island's Agricultural Station continues to import new species with potential for cultivation on the atoll (Teeb'aki, 1993;; AT, personal observation).

Geomorphology and Topography of Kiritimati Atoll
Although the common dictionary definition of atoll varies from a "ring-like coral island enclosing a lagoon" (Bryan, 1972) to "a circular coral reef or string of coral islands surrounding a lagoon" (Bryan, 1953;Wiens, 1962;, these definitions are too simplistic because most groups of atolls, like the Gilbert Group of Kiribati, consist not only of "true atolls" with lagoons, but also of other small, lagoon-less, low-lying limestone islands, sometimes referred to as "table reefs." Similarly, the "true atolls" often, like Kiritimati, have multiple lagoons, ponds or basins separated by reefs, sand bars, islets or portions of the main island, and are often far from really circular . Adapting the above definitions, the term "atoll" is here defined as a low-lying oceanic limestone reef island or group of islets, with or without lagoons, that has formed on a barrier reef, but which is not associated with a nearby high island or a continent. The term "islet" refers to the individual smaller islands or motu (a Polynesian name for reef islets) that are found on the reefs or in the lagoons of the main atoll island .
Most of the islands of the Republic of Kiribati consist of atolls, including "true atolls" with reefs and low-lying islets with limited land areas that encircle or partially encircle central lagoons and small, lowlying limestone or reef islands with no lagoons. Kiritimati Atoll is, however, very different. It is slightly higher, much larger and has a distinct and more diverse environment compared with the other atolls of Kiribati. The large land area of Kiritimati, its relatively small main lagoon and abundance of smaller lagoons are caused at least in part by uplifting, of which evidence can be seen particularly in the center of the island, where there are extensive raised coral benches.
Most of Kiritimati's land area is composed of one continuous surface which, unbroken by passes or channels to the ocean, almost completely encircles a central tidal lagoon with an area of about 160 km 2 ( Figure 2). There is a large peninsula, Southeast Peninsula, and a double entrance or pass to the open ocean in the west of the island, in the middle of which lies Cook Island (Islet). South and east of the main lagoon, the surface is covered by countless landlocked hypersaline pools or lagoons, with a total area of about 168 km 2 , in a matrix of limestone hardpan . The main tidal lagoon is connected by very small channels to Manulu and Ava Lagoons in the northeast. There are a number of islets within the main lagoon, the largest of which are Motu Tabu and Motu Upua , and some of the larger land-locked lagoons, such as Isles Lagoon, contain many small islets.
All of the names of places on Kiritimati mentioned in this article, except specific sites within a given village (e.g. buildings, installations, streets, fields etc.), are shown on Figure 2.

Climate
Kiritimati is located in the dry equatorial oceanic climate zone and receives an average annual rainfall of only 766 mm (30.2 in). Compared to Tabuaeran and Teraina to the north, which have average annual rainfalls of 2,086 mm (82.1 in) and 2,902 mm (114.3 in) respectively, Kiritimati is extremely dry. Based on an average monthly rainfall for Kiritimati from 1951-1988, the wet season normally falls from January to July, with the driest months being August to December, and the highest rainfall normally occurring during April. However, the climate is heavily influenced by the El Niño Southern Oscillation (ENSO) cycle, with longer (mostly 2-6 years) drier periods separated by shorter (1-2 years) high rainfall periods associated with El Niño events (Falkland and White, 2007). Droughts during La Niña stages of the ENSO, such as that of [2005][2006], have a serious impact on the vegetation and the resident bird populations. In 2006, a high percentage of the Tournefortia trees on the smaller islets and in drier, more exposed sites and low-lying sites on the mainland were dead, as were areas of Suriana, but these still served as rookeries or perches for seabirds. Many of the coconut plantations, such as those near Poland, had a witches'-broom appearance, with skirts of dead fronds hanging down the trunks of the trees, and other areas that were formerly open Lepturus herbland looked more like salt flats, with either dead or dormant remnants of formerly healthy bunches of grass.
Average rainfall has increased in Kiritimati since the 1950s but the rainfall has become more variable: droughts have become less intense, of shorter duration and with a longer period between droughts (Falkland and White, 2007). Whether this change is part of a longer-term oscillation in climate cannot be determined from the relatively short rainfall record. However, such a cycle could see a return to drier conditions, as existed during the earlier part of the 20th century.
Kiritimati experiences fairly strong winds throughout most of the year, which cause an additional desiccating effect, and have contributed to the existence of sand dunes, including Joe's Hill (the highest elevation on the island at about 15 m above sea level), and coral rubble mounds with a relatively high elevation compared to other atolls .

Water Resources
The only permanent freshwater resource on Kiritimati is groundwater in the form of "lenses" of often slightly brackish freshwater, hydrostatically "floating" on the higher density saltwater beneath the island. The height of a lens above sea level and the level of salinity vary in relation to the elevation and shape of islets and the amount of water use and rainfall. The major lenses are in the north of the island at Decca, Four Wells, Banana, and in the southwest at New Zealand Airfield; several minor lenses also occur (Falkland and White, 2007). Replenishment or recharge of the lenses is solely dependent on rainfall. In areas where the lens is close to the surface, pools are often found during excessively wet periods, especially during high tides .
The location and characteristics of the groundwater influence the nature of the vegetation as well as the location of village wells and cultivation pits. The quantity and quality of groundwater and the habitability of atolls are severely affected during times of extended drought, particularly in areas where the lens is less well-developed.
Studies since the 1960s indicate that the freshwater lens could yield about 1800 m 3 (1.8 million liters) per day if catchments could be cleared of trees (mostly coconuts) and shrubs, but this would reduce to around 1600 m 3 per day if coconuts are not cleared (Falkland and White, 2007). At an estimated per capita consumption rate of 90 liters per day, this suggests that, based on water availability alone, Kiritimati could support a maximum of approximately 20,000 people. However, the mismatch between the location of lenses and population centers that could support expansion suggests that a more realistic figure should be approximately 13,500 people (Falkland and White, 2007).

Soils
The soils and substrate of Kiritimati are very infertile. They include young calcareous soils, sandy soils, limited areas of hydromorphic soils, highly alkaline hardpans, and very limited areas of phosphaterich, guano-derived soils under seabird rookeries. In general, the soils are young, shallow, alkaline, coarse-textured and have carbonatic mineralogy. Because of their immaturity, they vary little from the original coral limestone parent material. They are composed of a variable layer of organic matter and coral sand, foraminifera, fragments of shells and other marine organisms overlaying a limestone platform (Morrison, 1987).
Based on research elsewhere in Kiribati, potassium levels are often extremely low, and pH values of up to 8.2-8.9 and high CaCO 3 levels make scarce trace elements, particularly iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), unavailable to plants. Activity of soil microorganisms is limited, soil waterholding capacity is very low because of coarse texture, and ground water is often saline. Fertility is highly dependent on organic matter to lower soil pH, to capture and recycle plant nutrients, and to retain soil water in the excessively fast-draining soils. These factors together make conventional agriculture, as practiced on other larger Pacific islands, almost impossible on Kiritimati. They also preclude the existence of many common native coastal and introduced species that are common on other atolls and small low-lying islands (Morrison, 1987; Although there is some organic matter in some areas of undisturbed soils in areas of higher water availability under natural vegetation, it can decrease dramatically as a result of clearance by fire or replacement by coconut plantations or other introduced plants. The unstable sandy areas of the island are likewise very nutrient deficient and, unless highly modified, only suitable for coconut cultivation and the planting or protection of indigenous coastal strand plants (Morrison, 1987;.

TERRESTRIAL AND LAGOON HABITATS
Terrestrial and lagoon habitats and major vegetation associations of ecological and economic importance on Kiritimati Island (adapted from   Although the terrestrial ecosystems, in most cases, directly correspond with different vegetation associations, the proximity and effects of the sea and lagoon ecosystems (e.g., the extensive network of hypersaline ponds, high waves and strong sea winds and associated salt spray) also contribute to the nature of the vegetation and flora of Kiritimati. Although some detail on plants is given under the individual habitats presented in this section, the main aspects of the vegetation are covered under the vegetation type and flora sections that follow.

Beaches
Kiritimati has many kilometers of unpolluted white-sand beaches that offer great potential for tourism development and serve as the interface between the terrestrial and marine ecosystems. Some of the main areas of extensive white-sand beaches include (1) the coastline from London extending north to Northwest Point and Cape Manning and along most of the north coast to Northeast Point; (2) the coast extending south from Joe's Hill, south of the Bay of Wrecks to Aeon Point; (3) the entire south coast from Southeast Point extending around Southwest Point to Benson Point on the west of the island; and (4) the lagoon-side of the island south of Benson Point and encircling reefs islets, such as Cook Island, Motu Upua and Motu Tabu .
The beaches are commonly bordered on the seaward margin by limestone substrate in the intertidal zone and by Scaevola scrub or Scaevola-Tournefortia strand or littoral forest on the landward side. In some areas on the outer coast, and more commonly on beaches within the lagoon, the succulent Sesuvium portulacastrum is found in the outpost littoral vegetation. On the windblown flats along the shores of St. Stanislas Bay north of Nei Naomi's Well are scattered Suriana maritima, Scaevola and Tournefortia, with scattered Heliotropium anomalum and Sida fallax and the semi-parasitic vine, Cassytha filiformis, climbing on some of the larger plants. Common fauna include ghost crabs te kaviki Ocypoda cerathopthalma and striate surf clams te katura Atactodea striata, as well as two land hermit crabs, known generally as te makauro, but specifically as te wi ura Coenobita perlatus and te wi ro C. rugosa, which are found in abundance straying from the surrounding vegetation or coral ramparts .

Coral Rubble Ramparts
There are also areas of extensive coral rubble ramparts composed of large, slab-like, water-worn and weathered hard coral pieces, some weighing over 10 kg. These ramparts, which in some places rise to up to 3-5 m above sea level, are an indication of the power of the waves and storm surge that affect some coasts of the island. The main concentration of these coral ramparts extends from Northeast Point south along the Bay of Wrecks to just north of Artemia Corner, and in scattered other locations on east-and west-facing coasts (e.g., about 1 km west of the Captain Cook Hotel and on the northwest coast of Cook Island). The fauna in these areas consists mainly of land hermit crabs and grapsid shore crabs te kamakama Grapsus albolineatus. These ramparts, especially along the Bay of Wrecks, are very scenic and constitute a unique island environment of considerable international importance .

Sand Dunes
There are a number of concentrations of well-formed sand dunes that have developed over thousands of years due to the strong winds and rough seas, and which rarely attain elevations greater than 2-3 m above sea level. The main concentrations of sand dunes (referred to locally as sand ridges) include (1) Joe's Hill, just to the south of the Bay of Wrecks, which attains an estimated elevation of 15 m above sea level; (2) a number of smaller, lower dunes just inland from the coast between Joe's Hill and Aeon Field; (3) some extensive dunes near the west end of Aeon Field; (4) a sand hill inland from Southeast Point; (5) some lower dunes about 1 km east of the Captain Cook Hotel; and (6) a small raised area of dunes on the east coast of Cook Island .
The vegetation of Joe's Hill is composed mainly of stands of Scaevola taccada and scattered Tournefortia argentea with Cassytha filiformis and scattered, often extensive patches of Lepturus repens and Boerhavia tetrandra, especially on the leeward western side of the dunes. There are also areas with small populations of Heliotropium anomalum and Portulaca lutea on the windward-facing eastern parts of the dunes.
These dunes, in particular Joe's Hill, are ecologically and geologically uncommon in the Pacific islands, and should be protected as reserve areas.

Sand-Clay Plains
Much of the interior of Kiritimati is made up of flat, low plains bearing a layer of sand-clay soils of varying thickness, derived from the coral substrate. Such areas carry all of the vegetation associations in the bulleted listed above and include the major areas that have been developed for settlements and plantations. They are thus among the most economically valuable habitat types.

Limestone Hardpans
There are extensive areas of limestone hardpan that form the matrix for countless hypersaline ponds. These areas are colonized by salt-tolerant scrub vegetation, dominated mainly by Suriana maritima, Scaevola taccada and Tournefortia argentea, with scattered Heliotropium procumbens, Sida fallax, Portulaca lutea and Cassytha filiformis. They offer little productive potential and constitute important seabird nesting areas, especially near Y Site and the Ngaon te Taake along the eastern side of the central lagoon. Like the sand dunes, they are unique landforms of some scenic and scientific importance and should be kept free from development, including solid waste disposal .

Lagoon Islets
There are a number of uninhabited islets in the main lagoon. Along with Cook Island at the lagoon entrance, Motu Upua and Motu Tabu are among the most important seabird nesting areas on Kiritimati and the most easily protected because of their isolation from the mainland. These three islets should continue to be designated protected, limited-entry areas to ensure that their wildlife and natural environments are preserved for the benefit of ecotourists, scientists and future generations of residents and students .
Cook Island also deserves recognition historically as the site where Captain James Cook became the first recorded European to land on the island when he "discovered" it on 24 December 1777 before spending Christmas Day somewhere on Kiritimati.

Lagoons
Kiritimati carries three main kinds of open water (lagoons). The main lagoon, which opens to the ocean in the west, is tidal with water salinity close to that of the open ocean. Much of the island is, however, made up of a network of smaller, more-or-less land-locked lagoons with many natural and artificial channels between them, which establish a wide range of tidal-salinity regimes. Many of the smaller land-locked lagoons become hypersaline through evaporation, although during periods of heavy rainfall their salinity can become so reduced that they become merely brackish.

NATURAL AND ANTHROPOGENIC VEGETATION TYPES
As listed in the bulleted list above, the main distinguishable "natural" (i.e., not anthropogenic) vegetation types on Kiritimati include Pisonia forest; Tournefortia woodlands; Tournefortia-Scaevola littoral forest and scrub; Scaevola, Suriana and mixed scrublands; and Lepturus and mixed herblands. The main anthropogenic vegetation types include coconut plantations, village and houseyard gardens, and ruderal vegetation, all in various stages of management. In many areas these vegetation types form a patchwork, intergrade with each other and constitute mixed categories or transition zones between vegetation types.

Pisonia Forest
Although Pisonia grandis is the dominant tree on many uninhabited atolls and atoll islets in Kiribati and elsewhere in the Pacific, there are only three stands of Pisonia on Kiritimati (Garnett, 1983). These are (1) a large stand of an estimated 200 or more large trees near K Site just inland from Southeast Point; (2) a grove of 70-100 trees on the north-central part of Motu Tabu; and (3) a small stand of trees on the northern part of the island southeast of the JAXA Tracking Station. Pisonia is the most important species used as seabird rookeries in many Pacific islands, and these stands are of critical ecological importance and should be protected as parts of a system of seabird sanctuaries .
The large stand near K Site, the only large Pisonia grove on the main island, is surrounded by Tournefortia woodland and shrubland, with much Sida fallax. Immediately southwest of the grove is an artificial mound-like hill about 6 m in elevation covering a bunker, which is almost totally dominated by Sida. Further inland from the grove is a Lepturus-Boerhavia herbland savanna with scattered Cassythafestooned Scaevola, behind which are some abandoned Artemia (brine shrimp) ponds, with Sesuvium growing along the edges and along the dividing banks.

Tournefortia Woodlands
Woodlands and scrublands, and in some cases small dense stands, of Tournefortia argentea, usually below 5 m in height but up to 10 m in places (Garnett, 1983), are the main inland vegetation type in many areas, and, depending on the site, grade into Scaevola or Suriana open scrubland and Lepturus grassland and mixed herbland. These are often composed of scattered low-stature Tournefortia trees with mainly Lepturus, Portulaca and Boerhavia in between and in more open areas such as on Cook Island, with extensive areas of Lepturus-Tribulus-Portulaca herblands and scattered Boerhavia, Sida, Heliotropium and sometimes Cassytha. There are also areas of scattered Scaevola and Suriana in coastal woodlands. As mentioned above, there are also remnants of Tournefortia woodland surrounding and near the stand of Pisonia inland from Southeast Point.
These woodlands, particularly on Cook Island, are important nesting sites, particularly for sooty terns, black and brown noddies, white terns, and the red-tailed tropicbird .

Tournefortia-Scaevola Littoral Forest and Scrub
Important in some areas are Tournefortia-Scaevola littoral forest and scrub, which are found on more protected sites in some areas of coastline on the mainland and on lagoon islets, such as Motu Upua, where there is Scaevola in the outer zone with Tournefortia just inland. On the north coast just east of the Captain Cook Hotel, there are almost monospecific stands of Tournefortia, whereas along the south coast and near Southwest Point, there are stands of mixed Tournefortia-Scaevola coastal forest lining the inner margins of the beach, often with Scaevola interspersed or on the ocean side of the Tournefortia. On Cook Island and Motu Upua a number of Cordia subcordata trees grow in the coastal zone, as do a number of scattered coconut palms, which may have been planted as part of conservation efforts .

Scaevola, Suriana and Mixed Scrubland
The most widespread and dominant vegetation type on the island is Scaevola scrubland (Garnett, 1983), which varies from extensive, almost monospecific stands to scattered clumps with open areas of grassland, herbland or low scrub in between. The latter formation is common on the less favorable, drier hardpans or more exposed coastal sites. In the northeastern part of the island between Cape Manning and Northeast Point, very low, windswept Scaevola scrub dominates the areas inland from the coral shingle rampart, with Heliotropium anomalum in scattered patches in some areas of coral shingle, and patches of Sesuvium on the inner portions of the coral rubble. There are also Portulaca-Sida-Boerhavia herblands and other mixed herblands, many of which are important nesting sites for some seabirds, including the great frigatebird, lesser frigatebird, masked booby and red-footed booby (which nest in Tournefortia and Scaevola scrub south of Y Site), and the blue-grey noddy (which nests in the natural camouflage of the Heliotropium-Portulaca-Sida herblands on Cook Island and Motu Tabu). On Motu Upua there are relatively dense areas of predominantly Suriana shrubland, mostly in sandier beachward sites.
To the east of Poland and in a number of other highly saline sites, such as around many of the hypersaline ponds, there are almost monospecific stands of Suriana maritima, which intergrades with Scaevola and other species, such as Heliotropium, on the margins. On sandy areas on the eastern coast of Cook Island, there are some almost monospecific areas of scattered Heliotropium with white sand in between.
Sida scrub, growing to 2 m high, is found particularly abundantly on the coastal plain along the south coast, but also occurs on sandy soils near inland ponds and the eastern shores of the main lagoon, associated with colonies of burrowing wedge-tailed shearwaters (Garnett, 1983). On the Southeast Peninsula and elsewhere the Sida is prostrate in habit and better described as forming a dwarf scrub (Garnett, 1983).
In open areas along the southern coast small patches of scrub or dwarf scrub dominated by Hedyotis romanzoffiensis with Lepidium bidentatum occur on limestone hardpan and rubble (Garnett, 1983).

Lepturus Grasslands and Mixed Herblands
There are extensive Lepturus grasslands in a number of sites on the island, including (1)  The dominant species in these areas is Lepturus repens, sometimes in almost monospecific open stands, often with sand in between in more coastal sites such as near Southwest Point. Other important species in the Lepturus and mixed herblands include Portulaca lutea, Tribulus and Boerhavia tetrandra, with scattered Tournefortia trees and commonly small populations or clumps of Scaevola or Heliotropium anomalum, both commonly festooned with Cassytha filiformis. There also sites near the hypersaline ponds and in sandy sites on lagoon islets, such as Motu Upua and Motu Tabu, where there are almost monospecific areas of Sesuvium. These constitute some of the more favorable bird nesting sites, especially for shearwaters Puffinus spp. and boobies Sula spp. Attempts should made to ensure the protection of the more favorable sites, particularly those on Cook Island, Motu Tabu, Motu Upua and south of Y Site .
In open areas in the scrubland, close to hypersaline ponds, there is a variable mixture of Lepturus, Heliotropium anomalum, Portulaca lutea and Sida fallax, often forming what amounts to a dwarf scrub rather than an herb-dominated formation (Garnett, 1983). Cassytha is also an important component, in some cases festooning the shrubby vegetation and trees or as a terrestrial creeping component of the herbaceous vegetation.

Other Natural Vegetation Types
In sandier sites, such as on the narrow isthmus south of the former South Pacific Airways Hotel, Suriana maritima is found along with Scaevola, Tournefortia and Cassytha. Herb mats with Heliotropium anomalum, Boerhavia, Portulaca lutea and Cassytha are found to the north of Poland on the peninsula.
Around the hypersaline ponds, which are affected by tidal fluctuations, there is often clear zonation, with Sesuvium mats growing closest to the ponds in areas most affected by high waves and salt spray during times of high winds and high tides, then Heliotropium on the slightly higher more well-drained areas, and then Scaevola or Suriana further inland, sometimes in almost monospecific stands and sometimes mixed. Sesuvium is also occasionally found along more protected beaches, such as on the northwestern side of Motu Upua. In some more sheltered sites there are also scattered individual trees or stands of Tournefortia. On the more exposed sandier, rockier or hardpan sites, such as on Ngaon te Taake, Suriana is more dominant, with Lepturus more common in sandier sites between the larger shrubs. Fimbristylis, probably a recently introduced species, seems more suited to areas where asphalt-like hardpans are found. Also found in drier, rockier sites are Sida fallax and Portulaca lutea.

Coconut Plantations
Although the main opportunities for export income and the generation of foreign exchange in Kiritimati are related to the marine resources, ecotourism and small developments such as the JAXA Tracking Station, coconut plantations and the other plants that people cultivate and protect in villages and houseyard gardens provide for some cash and many subsistence needs. They are the basis for sustainable living in the dry atoll environment of Kiritimati, and their protection, maintenance and perhaps further planting must be seen as integral to any further resettlement.
The coconut palm is still the "tree of life" to the I-Kiribati, and copra remains a source of livelihood for many people on Kiritimati. The income received is not great, but provides limited cash needed to purchase some necessities from the outside economy. Along with fish, coconut constitutes the main locally produced staple food. It is also the source of toddy (both sweet and fermented, made from the sap of the coconut flower spathe), fuel, medicine, thatch, timber, oil and a wide array of other products of economic and cultural value .
The most extensive coconut plantations are found in the south-central part of the island, and in the north between Cassidy Airport and Northwest Point. Scattered throughout the plantations, depending on the state of maintenance and disturbance, are elements of Lepturus grasslands and herblands, scrub and ruderal vegetation.

Village Gardens
Village and houseyard gardens contain a range of important food trees, crops and other culturally and ecologically valuable plants and ornamentals, most of which have been introduced to Kiritimati from the wetter Line Islands of Teraina and Tabuaeran or from the main Gilbert Group and Nauru (where many I-Kiribati have worked as contract laborers for years). There have also been numerous introductions from Fiji, Hawaii or other areas in Micronesia, such as Guam, which have, over the years, been the main direct air connections to Kiritimati. Important trees and shrubs in village gardens include coconut palms te ni Cocos nucifera, edible pandanus te kaina Pandanus tectorius, breadfruit te mai Artocarpus spp., tropical almond te kunikun Terminalia catappa, native fig te bero Ficus tinctoria, Alexandrian laurel te itai Calophyllum inophyllum, sea trumpet te kanawa Cordia subcordata, guettarda te uri Guettarda speciosa, noni te non Morinda citrifolia, beach hibiscus te kiaiai Hibiscus tiliaceus, frangipani te meria Plumeria spp., sebesten plum Cordia sebestina, hibiscus te roti Hibiscus rosa-sinensis, lantana te kaiboia Lantana camara, hedge panax te toara Polyscias spp., and a small range of other ornamentals.
Almost all of the plants cultivated in villages and houseyard gardens are culturally and economically essential for habitation on Kiritimati. The increased planting of trees and a wide range of other plants and the maintenance of small food gardens should be an integral component of all development programs on the island.

Ruderal Vegetation
Increasing urbanization, including the expansion of settlements and the development of roads, airports, schools and other infrastructure, has created extensive areas of continually disturbed ruderal vegetation. These include roadsides, pathsides, waste places, pigpens, open lots, unpaved areas around parking lots, airports and old landing strips, and other areas that are continually disturbed or not maintained (e.g., neglected houseyard gardens). Although indigenous species such as Lepturus repens are found in ruderal sites, these are the main places where easily dispersed, fast-growing, weedy shrubs, grasses, sedges and other herbs are found, most of which have been accidentally introduced over the past century.
Common introduced grasses (Poaceae) in ruderal areas include Cenchrus echinatus, Eleusine indica, Eragrostis tenella and Eustachys petraea, the last only seen since 1996 but now increasingly widespread. Other uncommon to rare grasses include Chloris barbata and Dactyloctenium aegyptium.
We found many more recently introduced species than had been reported before our studies. Up to 2012, many of these were still only present in cultivation, but some were already invasive, including Eustachys petraea (first recorded 2006), already among the most common and widespread introduced grasses, and Amaranthus dubius (1996), Heliotropium procumbens (2006) (2006); the generally dry climate and harsh soils of Kiritimati are presumably not suitable for them. Spermacoce assurgens was first recorded in the wet year of 2008, when it was common and widespread in the northwest of the island, but was not found thereafter; some other weeds may similarly only become evident under such unusually favorable conditions. A few other weedy plants, reported present in the past, seem never to have become common and perhaps have died out, including Cenchrus ciliaris (2006, one record), Panicum maximum (1934, one record), Verbesina encelioides (1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981)(1982), Sida rhombifolia (1924, one record).

TERRESTRIAL FLORA
The indigenous flora of Kiritimati is very limited due to the island's extreme isolation, low rainfall, frequent prolonged droughts and extremely poor soils. The latter factors also place limits on the establishment of species introduced by people. However, there has been extensive human disturbance for over a century, from coconut planting, military occupation of the island during World War II and for nuclear testing by the British and Americans in the 1950s and 1960s, and resettlement of the island by I-Kiribati from the more populous islands of the Gilbert group after independence in 1979. The following analysis is based on our own surveys from 1996 to 2012 and other species reported in the past (referenced in the species accounts).
The number of vascular plant species that have been reported at some time on Kiritimati, including all indigenous and introduced species (whether in cultivation or not) is 168, plus 3 hybrids and 3 additional varieties, for a total of 174 taxa, all of which are discussed in detail in the annotated list. Of these, three records are doubtful (two Boerhavia spp. and one Musa taxon), leaving a reliably reported total of 171 taxa in 166 species. Only 10 of the reported taxa (Eragrostis ciliaris, E. paupera, Panicum maximum, Verbesina encelioides, Barringtonia asiatica, Acalypha amentacea, Erythrina variegata, Macroptilum lathyroides, Sida rhombifolia, Waltheria indica) were not seen by RRT or AT, and of these at least six (Panicum maximum, Barringtonia asiatica, Acalypha amentacea, Erythrina variegata, Macroptilum lathyroides, Waltheria indica) have probably died out on the island, leaving an extant flora of around 165 reliably recorded taxa (including the hybrids and varieties) in 160 species.
The total flora, including the hybrids, varieties, doubtful taxa and those that may have disappeared, includes 42 monocotyledons and 132 dicotyledons. There have been no indigenous or introduced ferns or gymnosperms recorded on the island, although on the wetter northern Line Islands a number of ferns are found and a "few large" Araucaria pines were seen as planted ornamentals around the Cable Station on Tabuaeran in 1982 (Wester, 1985).

Indigenous and Questionably Indigenous Species
Of the 167 plant species reliably recorded on Kiritimati, probably only 15 (9%) or perhaps up to 19 are native; in other words, some 90% of the present-day flora is introduced. Only three monocotyledons, all grasses, appear to be indigenous: Digitaria stenotaphrodes, Eragrostis paupera and Lepturus repens. Lepturus is the only abundant indigenous grass on the island.
The most abundant indigenous woody species include te mao Scaevola taccada and te ren Tournefortia argentea, which are dominant in most coastal sites and in many inland areas, and te aroua Suriana maritima, which is particularly common in calcareous hardpan sites and on beaches on lagoon islets. Te kaura Sida fallax, te wao Boerhavia spp., te boi Portulaca lutea, and Heliotropium anomalum are herbaceous or subshrubby native species that dominate herbland sites, while te boi ntari Sesuvium portulacastrum dominates saline sandy and clay soils, especially around lagoon margins. The semiparasite te ntanini Cassytha filiformis commonly festoons vegetation throughout the island. Two less common indigenous dicotyledons are Lepidium bidentatum and Hedyotis romanzoffiensis, which are most abundant growing together on calcareous hardpan along the south coast.
Three species indigenous to some central Pacific islands, including other Line Islands, and sometimes considered native to Kiritimati but more likely introduced there by people include the sedge Fimbristylis cymosa, which was not recorded until 1962, and the useful plants te buka Pisonia grandis and te kanawa Cordia subcordata, which were perhaps introduced by early Polynesian visitors or during the early European colonization period. The seabird-dispersed Pisonia grandis was first recorded in 1924 and is found in three isolated stands, one on Motu Tabu, one inland from the JAXA Tracking Station near Northwest Point, and one near K Site on the Southeast Peninsula. The seawater-dispersed Cordia subcordata is found in a few coastal locations in the northern part of the island, the Southeast and Paris peninsulas, and on lagoon islets. It was not reported until the 1970s by Roger Perry, who considered it introduced, and the current trees, although found in coastal vegetation, may be descendants of deliberate plantings.
Three more species useful to people that are even less likely to be native to Kiritimati include te kiaiai Hibiscus tiliaceus, also dispersed by floating seeds and first reported in 1924, but then and since only recorded in settlements or persisting from former cultivation (as at Paris). Pandanus te kaina Pandanus tectorius was also first reported in 1924, but has only been found where clearly planted by people. The coconut palm Cocos nucifera was first documented by Captain Cook in 1777, in a grove most likely planted by Polynesians. Any of these species could conceivably have arrived naturally at one time or other in the past, but the extant populations all seem to derive from introductions by people.
Abutilon indicum, probably also known as te kaura (same name as for Sida fallax), is a problematic species whose records suggest it might be indigenous, although it is not known to be native elsewhere in Oceania. It is rare but was recorded in 1936 and the 1980s in sites where it seems unlikely to have been planted deliberately or introduced unintentionally. However, in 2006 it was found planted in one garden, possibly from a separate introduction by people.

Introduced Flora
The introduced flora includes a range of grasses, sedges, herbs and other weedy species, plus cultivated food plants, ornamentals and other useful plants, some of which have naturalized. Some 54 species, including both unintentional introductions and escapes from cultivation, have naturalized, while the evidence for an additional five having naturalized remains inconclusive to date.
Useful species have been deliberately planted on Kiritimati at least since its European discovery. Cook (1874) planted yams, melons and coconuts on Cook Island, which could not be found by Bennett (1840), while the crew of Bennett's ship planted there "seeds of celery, pumpkin, and orange; as well as arrow-root, sweet-potatoes, and turmeric-root," which do not seem to have survived either.
Some species that are indigenous to other islands of Kiribati are certainly introduced on Kiritimati. Many of these are only found in settled areas. Some widespread coastal strand plants that are indigenous to the region, including the wetter inhabited islands in the Lines group (Teraina and Tabuaeran), and islands of the Gilbert group, appear to have been introduced by humans to Kiritimati from these islands. These include (first records in parentheses) the prostrate herb te kiaou Triumfetta procumbens (2006; an important I-Kiribati medicinal plant), the vines te ruku Ipomoea macrantha (1996) and te kitoko Vigna marina (1996), the shrubby scrambler te inato Clerodendrum inerme (c. 1980), and the trees te itai Calophyllum inophyllum (c. 1980), te uri Guettarda speciosa (1964), te kiaiai Hibiscus tiliaceus (1924), te non Morinda citrifolia (c. 1978), te ango Premna serratifolia (1996), te kunikun Terminalia catappa (c. 1978) and te ukin T. samoensis (1996). All of these are found cultivated in houseyard and village gardens.
The useful trees casuarina te katurina Casuarina equisetifolia (1964) and leucaena te kaitetua Leucaena leucocephala (1936) are both established and the former is common in settlements.  (1996), and the annuals marigold te merikora Tagetes erecta (1996) and zinnia te tinia Zinnia violacea (1996). Ornamentals seen only as single specimens included bauhinia Bauhinia malabarica ( ), croton Codiaeum variegatum (1996 and sunflower Helianthus annuus (1996); some of these may have since died out. The most common street trees seen in London were Calophyllum inophyllum, Cordia subcordata, Terminalia catappa and Hibiscus tiliaceus, all indigenous to the Pacific islands but probably introduced deliberately to Kiritimati.
New useful plants continue to be introduced to the island, some of them introduced by the Agricultural Station, with the following seen only there and only since 2008: taro te taororo Colocasia esculenta (

INTRODUCTION TO THE ANNOTATED LIST
In the annotated list that follows, we present the monocotyledons before the dicotyledons, with each group organized alphabetically by families, then genera, and then species.

Plant Status
We categorize the abundance of plants as follows: Introduced and Exotic -Species known or considered to have been introduced to the island deliberately or unintentionally by people. Indigenous and Native -Species thought not to have been introduced by people.

Recent introduction -Species introduced since Captain Cook's visit (1777). Aboriginal introduction -Plants probably introduced by earlier Polynesian or Micronesian visitors.
Extirpated -The species once occurred on Kiritimati (known from reliable records) but does so no longer; in most cases we state "probably" extirpated, since the possibility remains that a species has been recently overlooked. In some cases, a species may have arrived and established itself naturally, subsequently disappeared (become extirpated) due to some extreme event, such as a prolonged drought, storm surge or tsunami, and then been deliberately or accidentally reintroduced by humans.

Abundance
We categorize the abundance of plants as follows: Very abundant -Abundant in large areas or most habitats, and dominant in many sites or habitats. Abundant -Widespread in a range of habitats, or dominant in several different habitats throughout the island. Common -Found in many locations but not dominant, or locally abundant or dominant in a few locations. Occasional -Occasionally seen but in a number of places, or locally common in only a few locations. Uncommon -Found in only a few locations, including in undisturbed sites, as remnants in previously settled areas, or in a few houseyard gardens or experimental agricultural areas. This category could also pertain to plants, such as annual flowers or food plants, that are seasonally planted and were not common during the periods of the surveys. Rare -Found in only one or two locations. Such species may be in danger of extirpation, and include rare ornamentals, food plants, etc., and recent trials that may not prove suited to the Kiritimati environment.

Plant Records and Recorders
Most of the early plant recorders who collected or made observations on Kiritimati focused mainly on the native and naturalized vegetation. In some cases there was little cultural vegetation due to the limited settlement at the time.
In each species account, we list records in chronological order using abbreviations for the recorder's or recorders' names and years of record, as follows. Dates refer to the periods when the collections or observations were made. We provide an expanded listing of these plant recorders, including affiliations, publications, and other collection details, in the Appendix.  1934EHB 1935-1938-E. H. Bryan F&M 1936-F. Raymond Fosberg and Alfred Metraux, August 1936LWB 1945-L. William Bryan, October 1945WFC 1957-Captain W. F. Curlett, June 1957FLH 1957-F. L. Hill, October and November 1957JPG 1958-Corporal J. P. Griggs MDG 1958-Michael D. Gallagher, June 1958-June 1959DCH 1962-Dean C. Hamilton, April 1962CRL 1964-C. R. Long, June and November 1964, June 1965-W. A. Sledge, April 1965RNJ 1965-R. N. Jenkin, August-September 1965RP 1977-1979-Roger Perry, in residence 1977-1979MCG 1979-1982-Martin C. Garnett, in residence 1979-1982RWH 1982-Robert W. Hobdy, January 1982LLW 1982-Lyndon L. Wester, August 1982RRT 1996-Randolph R. Thaman, July 1996HLJ 1997-H. Lee Jones, May 1997RRT 2006-Randolph R. Thaman, May-June 2006, 2009, 2011, 2012-Alan Tye, April 2008, September 2009, March 2011, March 2012 For example, "RRT 1996; AT 2009" indicates that the species was found by Thaman and Tye, respectively, in those years. Where AT has examined a specimen collected by someone else, this is indicated by "[AT!]" placed after the recorder's abbreviation and specimen number, followed by the holder of the specimen, (e.g., "DCH 1962, specimen 1[AT!] at BISH"). When an actual specimen is referenced, the recorder's abbreviation may be replaced by the full last name of the collector. This convention is used to identify which member of the group collected the specimen when the abbreviation identifies two or more collectors (e.g., "Fosberg 1936, specimen 12170[AT!] at BISH" rather than "F&M 1936, specimen 12170[AT!] at BISH").

Voucher Specimens
Voucher specimens collected by RRT (in 1996 and and AT ( -2012 and deposited at SUVA, the South Pacific Regional Herbarium at The University of the South Pacific (USP), Suva, Fiji, are cited by collector's number thus: "USP" followed by a serial number indicates an RRT voucher specimen; "AT X" followed by a number and locality indicates an AT voucher specimen.

Digital Voucher Photographs
Most species have voucher photographs taken by RRT in 2006-2012. When such photos are available for a species, they are listed thus: RRT's photos are cited as "DPKR0001, 0002…," with DPKR referring to Digital Photo KiRitimati, and with lower case letters a-e after a number indicating the position of the species in the photo when the photo features more than one species, designated by a (first of two or more species in the photo), b (second of two or more pictured species), c (third of two or more pictured species), d (fourth of two or more pictured species) or e (fifth of two or more pictured species). AT's photos are cited in the form ATYYYYMMDD_nn, for example, AT20090922_38 means photo 38 (of this taxon) taken on 22 September 2009.
The voucher photographs either validate the presence of a species or help confirm its identity. They include close-ups of leaves, branches and trunks or stems of plants with floral and fruiting parts; entire plants; and landscape shots to show the preferred habitats of the species. These digital photos have been copied into computer files in both the School of Geography, Earth Science and Environment and the South Pacific Regional Herbarium at The University of the South Pacific, Suva, Fiji, and in the Agricultural Division at Tenaea and the University of the South Pacific Centre in Teaoraereke, on Tarawa.

CLUSIACEAE (MANGOSTEEN FAMILY)
Calophyllum inophyllum L. One large tree in the cemetery outside London. Fine hard, fine-grained wood used in canoes, for canoe paddles and in traditional skindiving goggles; fruits used in children's games; kernels crushed and oil extracted, which is spread on sores; juice from roots mixed with water to treat headaches; also used to treat morning sickness, chicken pox and conjunctivitis; flowers used to perfume coconut oil; skin and outer flesh of the fruit can be eaten; flowers used in garlands. Recorded: MCG 1979-1982RRT 1996RRT , 2006, 2009Voucher Photographs: DPKR0177a, 0681, 1260, 2020, 2022, 2389, 2457; AT20080425_01

NYCTAGINACEAE (FOUR-O'CLOCK FAMILY)
Almost all writers on the flora of Kiritimati have remarked that the systematics of the genus Boerhavia need attention (e.g. Christophersen, 1927;Fosberg, 1978Fosberg, , 1988Wester, 1985). C.R. Long made a large collection of Pacific Boerhavia, most of which is at BISH, as are many Boerhavia specimens collected by others, such as Fosberg and Wester, from Kiritimati and other Line and Phoenix islands. Most of CRL's and many of these other Boerhavia are sp. indet., including plants with white, pink or purple flowers, perennial or annual, a range of pubescence, and stems up to 8 m long. CRL collected many more Boerhavia than any other plant and was obviously interested in sorting them out, or helping someone else to do so. That job remains to be completed for Pacific Boerhavia (including molecular investigation), although some progress has been made (N.A. Douglas, pers. comm.).
We are unable to assign most of our own records with confidence to any particular taxon, and have dealt with them and previous records below by referring them to the taxa accepted by Fosberg (1978). Fosberg (1978) considered two major groups of species in the Indo-Pacific region, the B. diffusa group with strictly terminal, paniculate inflorescences, and the B. repens group (which includes B. tetrandra) with axillary, cymous or umbellate inflorescences. Following Fosberg (1978), in the BISH collection (when consulted by AT in 2010) B. diffusa was recognised as clearly separate from B. tetrandra and B. repens, but many BISH specimens of the plant that is widespread on Kiritimati, that is, what we here and others have called B. tetrandra, were classified under B. diffusa. Formerly, tetrandra (but not repens) was regarded as a subspecies of diffusa, so each Kiritimati record of "diffusa" needs assigning carefully to one of these two (or three) species. The native distribution of B. repens sensu stricto is only from Africa to Malesia, so Pacific specimens of the repens group should be B. tetrandra (Fosberg, 1978), unless they represent recently introduced populations.
Some Pacific white-flowered plants have been assigned to B. albiflora (described from the Phoenix Islands by Fosberg 1978 and placed in the B. repens group), but we are not confident that white-flowered plants on Kiritimati have been correctly distinguished from white-flowered B. tetrandra (or another species), as apparently treated by Christophersen (1927) and other authors on the Kiritimati flora. Apart from flower color, the major characters distinguishing albiflora from tetrandra were number of stamens, pubescence on the perianth and a tendency in albiflora for the leaves to reduce in size distally along the stem (Fosberg, 1978). We have found plants with white, pink or purple flowers, including both white and pink on the same individual, white-flowered and pink-flowered plants whose leaves reduce along the stem and others whose leaves do not reduce, and white-flowered plants with up to 4 stamens. We have not found plants with only terminal inflorescences or strictly red (rather than pinkish) flowers, which are the key characters of B. diffusa (Fosberg, 1978;N.A. Douglas, pers. comm.), so this taxon may not exist on the island. We have therefore placed almost all records within B. albiflora and B. tetrandra below, while leaving open the possibility of the presence of B. repens as a recent introduction, and recognizing that this

TILIACEAE (LINDEN FAMILY)
Triumfetta procumbens Forst. f. plants: leaves used medicinally, after boiling and applied to swollen limbs as a treatment for stonefish stings; leaves and stem tips boiled in water for a few hours used as a medicine with many applications, such as a disinfectant for bath water for babies, to reduce labor pains, to treat rashes and prickly heat; leaves mixed with coconut oil applied to septic cuts and sores; leaves boiled with toddy to clarify it; plant used in love magic and to treat diseeases due to te anti (ghosts and spirits). Recorded: RRT 2006;, 2009Voucher Photographs: DPKR1201, 1202, 1203, 1204; AT20080428_08, AT20090922_34

VERBENACEAE (VERBENA FAMILY)
Clerodendrum inerme L. Reported by locals to have been introduced to Kiritimati from wetter atolls in the Line Islands. There seem to be two varieties, one with smaller, darker green leaves and another with larger, lighter green leaves, similar to plants seen in the Gilbert Islands. Leaves mixed with coconut cream applied to open sores; used in treating prickly heat (te nimariri); used as a hair dye, to darken hair; leaves and flowers used in garlands. Recorded: MCG 1979-1982RRT 1996RRT , 2006AT , 2009AT , 2011AT , 2012 Voucher Specimen: AT X027 London Voucher Photographs: DPKR0132, 0133, 0135, 0297, 0318, 0732, 1990 Lantana camara L. Camp in 2011, suggesting that it was used as a cultivated ornamental from the 1950s. Only occasional in 1996, but by 2008 commonly planted in all settlements. A serious invasive in many parts of the tropics but not reported as naturalized in Kiritimati until 2009, when found apparently growing wild and spreading in waste places near the wharf in London. Flowers used in garlands; flowers said to be used by some people to treat infantile diarrhoea. Poisonous, although children are said to eat the fruits. Recorded: MCG 1979-1982RRT 1996, 2009, 2011, 2012Voucher Photographs: DPKR02024, 0313, 0314, 0763, 1251, 1252, 1630, 1889, 2456; AT20080426_02, AT20090918_02, AT20090918_04 Premna serratifolia L. Common Name: False elderberry, premna Kiribati Name: te ango Status: Indigenous to the region but probably a recent introduction to Kiritimati. Indopacific. Abundance: Occasional. Remarks: Not reported before 1996, and so far seen only where probably planted. Tree in houseyard gardens and occasionally along roadsides, in London, Tabwakea and Banana; also planted at the Captain Cook Hotel. Wood used in house construction and formerly to make fire by friction; straight sprouts and limbs used for fishing poles; roots used to perfume coconut oil; leaves used to treat sinusitis, as poultices for painful limbs; finely cut leaves boiled to treat post-partum haemmorhage. Recorded: RRT 1996RRT , 2006AT 2009AT , 2012 Voucher Specimen: AT X017 Captain Cook Hotel Voucher Photographs: DPKR0217, 0218, 2376, 2377, 2441, 2442, 2443, 2480; AT20090922_16, AT20090922_17, AT20090922_18

ZYGOPHYLLACEAE (CALTROP FAMILY)
Tribulus cistoides L. Common Names: Goat head, puncture vine, caltrops Kiribati name: te maukinikin Status: Probably a recent introduction to Kiritimati although perhaps indigenous to the region. Origin uncertain but now pantropical, and widespread in Polynesia and Micronesia including the Gilbert, Phoenix and Line Islands. Abundant. Creeping herb with thorny fruit, in 1924 found only in the northwest, scattered among Lepturus and Sida fallax in dry areas. In 1965 found mainly near Poland and at the base of the Paris peninsula. Common and widespread by the late 1970s, when found throughout the northwest, near the airport, around Poland and Dakota Strip, and scattered through the central lagoon area, including on many lagoon islets (MCG map). Today, is still most common and sometimes dominant in waste places and ruderal sites throughout the island, in villages, old military sites and other sites where spread by people, even in the southeast (e.g., near Dakota Strip and along roads and tracks). Not found in 1997 or 2010-2011 around the ruins of the old South Pacific Airways Hotel on the Paris peninsula. Particularly common on open sandy ground, including some sites away from human habitation, such as in some open herblands and on the bird islands of Motu Upua, Motu Tabu and Cook Island, but uncommon on Ngaon te Taake Islet. Remains common even after dry periods when most ruderals disappear, such as in early 2011. In March 2012, after one month of rainy weather, carpeted large areas between London and Tabwakea, and elsewhere. Possibly still spreading rapidly; known as highly invasive in other parts of the tropics. Recorded: C&B 1924;FLH 1957;MDG 1958MDG -1959DCH 1962;RNJ 1965;RP 1977RP -1979MCG 1979MCG -1982LLW 1982;RRT 1996RRT , 2006HLJ 1997;AT , 2009AT , 2011AT , 2012