Flora of Cook Islands

Acalypha wilderi was a species of spurge that was only known from forested habitats along the northern and western sides of Rarotonga in the Cook Islands, at elevations of 200–300 m. Very little is known about this species, but collections suggest it was a small shrub rarely exceeding 2 m in height. Its habitat has been greatly modified for agriculture, roads, housing, plantations and invasive species, and has not been seen since 1929, and was declared extinct in 2014. This species may be synonymous with A. raivavensis and A. tubuaiensis. The reason for its extinction is unknown.

Habenaria amplifolia is a species of orchid also called the Rarotonga ground-orchid. It is endemic to Rarotonga, growing in inland valley-bottoms and terraces. It is considered to be seriously endangered by the Cook Islands Government.

Homalium acuminatum, the Cook Islands homalium, is a species of tree in the willow family, Salicaceae. It is endemic to the Cook Islands, growing on the islands of Rarotonga, where it is known as mato, and Mangaia, where it is known as moto. It grows to a height of up to 20 m (66 ft). On Rarotonga it dominates steep mountain slopes. The IUCN Red List calls it the Rarotonga homalium and considers it endemic to Rarotonga, though the Cook Islands Biodiversity Database lists it as also present, but "uncommon" on Mangaia.

Garnotia cheesemanii, the Rarotongan garnotia grass, is a species of grass in the family Poaceae that is endemic to the island of Rarotonga in the Cook Islands in the South Pacific. The species is classified as Critically Endangered because of its extremely restricted range and population fragmentation.

Geniostoma sykesii (also known as Ange, or Makatea Geniostoma) is a species of flowering plant in the family Loganiaceae, endemic to the islands of Mangaia and Mitiaro in the Cook Islands. It grows on makatea (uplifted fossilised coral) terrain. Its dried leaves are used in ‘ei (floral necklaces), and used to scent multiple products.

Coprosma laevigata, the Rarotongan coprosma, is a herbaceous plant, a member of the Rubiaceae family.

Myrsine cheesemanii, known as the Cook Islands myrsine or ka‘ika makatea (in Mangaia), is a species of shrub within the family Myrsinaceae. It is endemic to the Cook Islands, growing on the islands of Rarotonga, Mangaia, Mauke and Mitiaro.

Myoporum wilderi, commonly known as Cook Islands myoporum or ngaio, is a plant in the figwort family, Scrophulariaceae and is endemic to the islands of Mangaia and Mitiaro in the Cook Islands. It is similar to Myoporum stokesii and Myoporum rimatarense which grow on other Pacific Islands. On the island of Rarotonga it is used to add a scent to coconut oil.

Psychotria whistleri, the Rarotonga psychotria, is a herbaceous plant, a member of the Rubiaceae family.

Pittosporum rarotongense (known as the Cook Islands pittosporum, kavakava or Mimi-ō-‘Ina) is a species of shrub or small tree in the family Pittosporaceae. It is endemic to the Cook Islands, growing on the islands of Rarotonga, Mangaia, Mauke and Mitiaro. On Rarotonga, it grows inland in the island's temperate cloud forest habitat.

Kalanchoe pinnata, commonly known as cathedral bells, air plant, life plant, miracle leaf, and love bush, is a succulent plant native to Madagascar. It is a popular houseplant and has become naturalized in tropical and subtropical areas. The species is distinctive for the profusion of miniature plantlets that form on the margins of its leaves, a trait it has in common with some other members of Bryophyllum (now included in Kalanchoe).

Pritchardia mitiaroana, the Mitiaro fan palm or Iniao is a species of palm tree that is native to the island of Mitiaro in the Cook Islands. It grows on karst limestone on the island's makatea (fossilised uplifted reef), and grows to a height of 10m. While previously believed to only be found on Mitiaro, in 2007 several clusters of fan palms on the islands of Niau and Makatea in the Tuamotus in French Polynesia were classified as belonging to the same species. Rarotongan oral histories record that there was once a strong sea route between Niau, the southern Cook Islands, and the Marquesas,

Cyperus marquisensis is a species of sedge that is native to the Cook Islands and the Marquesas Islands in the Pacific Ocean.

Carex stokesii is a sedge that is native to the Cook Islands and the Tubuai Islands.

Charpentiera australis is a species of flowering plant in the family Amaranthaceae. It is a tree or shrub native to Rarotonga in the Cook Islands, and to Raivavae and Tubuai in the Tubuai Islands of French Polynesia. It grows in lowland rain forests from 100 to 370 metres (330 to 1,210 ft) elevation. The range and population of the species is very limited. The species' population is estimated at 50 mature individuals on the three islands, with an area of occupancy (AOO) is 8 square kilometres (3.1 sq mi) on Raivavae. There are fewer than 10 subpopulations on the three islands, with only one

Asplenium schizotrichum is a species of spleenwort that is native to the island of Rarotonga in the Cook Islands and Niue. Its population on Rarotonga is estimated to be fewer than 20 mature individuals. The species was described in 1931 by Edwin Copeland.

Charpentiera is a flowering plant genus in the family Amaranthaceae. It consists of five species endemic to Hawaiʻi, where they are known as pāpala, and one species found only on the island of Tubuai in the Austral Islands. All species are trees, some reaching more than 10 metres (33 ft) in height. The genus is named for Arsène Charpentier (1781-1818), professor of pharmacy at Antwerp from 1810 to 1814 and at Cherbourg from 1814 to 1816.

Pterophylla affinis, formerly known as Weinmannia affinis, is a species of plant in the family Cunoniaceae. It is native to Fiji and the Samoan Islands.

Cyperus macrophyllus is a species of sedge that is native to the Cook Islands, Pitcairn Islands, and Society Islands in the Pacific Ocean.

Sideroxylon polynesicum, the keahi or island nesoluma, is a species of flowering plant in the family Sapotaceae. It is found in the Cook (New Zealand), Tubuai (French Polynesia), and Hawaiian Islands (United States). It is threatened by habitat loss.

Phyllanthus societatis is a species of flowering plant in the family Phyllanthaceae, native to Nauru, the Cook Islands and the Tuamotus, in the Pacific Ocean. The species was first described in 1866 by Johannes Müller Argoviensis.

Vaccinium cereum is a species of flowering plant in the heath family, Ericaceae. It is a shrub native to the Cook Islands, Marquesas Islands, and Society Islands in the South Pacific. In the Marquesas Islands it inhabits dry and windswept mountaintops above 1,200 m, where it is a characteristic shrub in heathland growing up to one meter tall, together Metrosideros collina, Styphelia tameiameiae, and Bidens spp., and interspersed with grasses and ferns. On Tahiti it grows on windswept razor-back ridges from 800 to 1400 meters elevation. Three subdivisions are accepted: Vaccinium cereum subsp.

Tetramolopium is a genus of plants in the tribe Astereae within the family Asteraceae. Most of the species are native to New Guinea, 11 species are found in Hawaii, and one in the Cook Islands, with the island populations apparently representing a recent (by evolutionary standards) colonization. It is related to Camptacra, Kippistia, Minuria, Peripleura, and Vittadinia all of which are from Australia, New Guinea, New Zealand, or Pacific islands. Species formerly included see Diplostephium Tetramolopium ochraceum - Diplostephium ochraceum Tetramolopium phylicoides - Diplostephium phylicoides

Fitchia is a genus of flowering plants in the sunflower family, native to certain islands in the Pacific. Species

Sclerotheca is a genus of plants native to various islands in the South Pacific. Nine of the ten species are native to French Polynesia, the tenth to Rarotonga in the Cook Islands. Sclerotheca arborea (G.Forst.) A.DC. – Tahiti Sclerotheca forsteri Drake – Moorea, Tahiti Sclerotheca jayorum J.Raynal – Tahiti Sclerotheca longistigmata F.Br. – Marquesas Sclerotheca magdalenae J.Jacques – Tahiti Sclerotheca margaretae R.Br. – Rapa Sclerotheca oreades E.Wimm. – Tahiti Sclerotheca raiateensis (Baill.) Pillon & J.Florence – Raiatea Sclerotheca seigelii (J.Florence) Pillon & J.Florence – Marquesas

Santalum insulare is a species of flowering plant in family Santalaceae. It is a shrub or tree native to the south-central Pacific, including the Cook Islands, Marquesas Islands, Pitcairn Islands, Society Islands, and Tubuai Islands. Seven varieties are recognized: Santalum insulare var. alticola Fosberg & Sachet – Society Islands Santalum insulare var. hendersonense (F.Br.) Fosberg & Sachet – Henderson Island (Pitcairn Islands) Santalum insulare var. insulare – Miti'aro (Cook Islands), Society Islands, and Tubuai Islands Santalum insulare var. marchionense (Skottsb.) Skottsb. – Marquesas

The genus Pritchardia (family Arecaceae) consists of between 24 and 40 species of fan palms (subfamily Coryphoideae) found on tropical Pacific Ocean islands in Fiji, Samoa, Tonga, Tuamotus, and most diversely in Hawaii. The generic name honors William Thomas Pritchard (1829–1907), a British consul at Fiji.

Metrosideros collina is a species of flowering plant in the family Myrtaceae. It is a tree or shrub native to French Polynesia, the Cook Islands, and the Pitcairn Islands.

Mussaenda raiateensis, commonly known as the Pacific mussaenda or Pacific flag-tree, is a plant of family Rubiaceae native to Tonga, Samoa, the Cook Islands and Society Islands in the South Pacific Ocean.

Ascarina diffusa is a species of flowering plant in the family Chloranthaceae. It is native to the tropical Pacific, ranging from the Bismarck Archipelago through the Solomon Islands, Vanuatu, Fiji, and the Samoan Islands to the Cook Islands. On Rarotonga in the Cook Islands, Ascarina diffusa is a characteristic tree of cloud forests above 400 meters elevation, becoming dominant or co-dominant with Metrosideros collina in higher and wetter cloud forest areas.