Flowering plants of Norfolk Island

Flowering plants of Norfolk Island

Three of our botanists recently spent a week on Norfolk Island collecting ferns with colleagues from the Royal Botanic Gardens Victoria. Our fern findings will be detailed in a future blog post but here we discuss interesting flowering plants that we saw – some of which were very familiar to us as New Zealanders but others were completely new!

Norfolk Island is around 625 km northwest of New Zealand, about halfway between New Zealand and New Caledonia. It is a small island measuring only about 8 km by 5km.

An image of a globe mostly showing the Pacific Ocean. Australia is coloured red and there is a circle around a small island between Australia and New Zealand.
The location of Norfolk Island (circled), a territory of Australia. Illustration by TUBS via Wikimedia Commons CC BY-SA 3.0

Along with two even smaller nearby islands, Phillip and Nepean, it forms the Territory of Norfolk Island.

A small island in the distance on a cloudy day. There are trees in the foreground.
View from Norfolk Island across to Phillip Island. Photo by Leon Perrie

Norfolk Island is the remains of an old volcano that started erupting around 3 million years ago but has been dormant for the last 2 million years.

Rocks poking up from the sea along a coast. There are trees on the coastline.
Most of Norfolk Island’s coastline consists of steep cliffs, reflecting its volcanic origins. Photo by Lara Shepherd

Some things exist in isolation

The isolated position of these islands means that the approximately 180 native vascular plant species arrived by dispersal. Consequently, the plants have affinities to the floras of surrounding land masses, particularly New Zealand, New Caledonia, and Australia. But there has been sufficient time for new species to evolve: 46 plant species are endemic to Norfolk Island (found nowhere else).

Much of Norfolk Island has been cleared for agriculture with only around 15% of the land protected in reserves. Norfolk Island National Park is the largest reserve and it encompasses the higher elevation parts of the island, including Mount Bates, the highest point at 319 m. The National Park also has the most intact indigenous forest and was where we spent most of our time.

Ferns in the undergrowth of a forest.
Indigenous forest in filmy fern gully, Norfolk Island National Park. Photo by Leon Perrie

The Territory of Norfolk Island has many threatened plant species. In 2003, 11 species were known from fewer than 50 mature plants! Propagation has since increased the numbers of these plants but 46 plant species, including 31 endemics, remain threatened. This is approximately 40% of the native plants on the islands.

Phillip Island hibiscus flower - a white flower with pink in the middle of the petals around the stamens.
Phillip Island hibiscus (Hibiscus insularis). This critically endangered species is endemic to Phillip Island, although it is possible that it also originally occurred on Norfolk Island. Grazing pressure reduced it to two clumps of plants on Phillip Island. Members of each clump are genetically identical clones. Its numbers have since increased through propagation and it has been planted on Norfolk Island. Photo by lukehalpin via iNaturalist CC BY-NC 4.0

Known by any other name

Over the course of our week-long fieldtrip, we saw many of Norfolk Island’s plant species. A number of species are shared with New Zealand, although some of the Norfolk Island plants have been classified as different subspecies.

Wide green leaves in the undergrowth.
Peppertree (Piper excelsum subsp. psittacorum). This is the same species, but a different subspecies, to New Zealand’s kawakawa. We thought it looked quite distinct from kawakawa. This subspecies also occurs on Lord Howe Island and the Kermadec Islands. Photo by Lara Shepherd
Green leaves on a bush in the sunshine.
Shrubby creeper (Muehlenbeckia australis). Only 100 plants of this species were known from Norfolk Island in 2003, but numbers have since increased. This vine is common in New Zealand, where it is known as pohuehue. Photo by Leon Perrie
Looking up through the palm tree fronds at the sky.
Norfolk Island palm/Niau palm (Rhopalostylis baueri), the only native palm on the island. This species also occurs on New Zealand’s Kermadec Islands and looks very similar to the nīkau palm found elsewhere in New Zealand. Photo by Leon Perrie
A lot of green leaves on a shrub. The leaves are quite long in length.
Akeake (Dodonaea viscosa subsp. viscosa). This subspecies also occurs in New Zealand and Australia. Photo by Leon Perrie
A flash-photo of long young tree stems that have leaves coming off the top of them.
Whiteywood (Melicytus ramiflorus subsp. oblongifolius). This subspecies only occurs on Norfolk Island and some consider it should be a recognised as a full species. In New Zealand we have māhoe (Melicytus ramiflorus subsp. ramiflorus). The leaves, white trunk and purple berries of the two subspecies are similar. Photo by Lara Shepherd
A cabbage treetop view with some land in the background. Further back is the sea with an island sitting in it. There is also a large cloudy sky.
Ti (Cordyline obtecta). This species also occurs on the Three Kings Islands off the northern tip of the North Island. Ti is related to New Zealand’s cabbage tree (tī kouka, Cordyline australis) but has larger, shinier leaves. Photo by Leon Perrie

A number of plants on Norfolk Island have similar-looking relatives in New Zealand but belong to different species. For many of these, we could determine the genus because they looked so similar to New Zealand species with which we are familiar.

two small white five-petal flowers and buds surrounded by leaves. The petals have double lines of pink dots on them.
Popwood (Myoporum obscurum). Only five plants of this endemic species were known in 2003. Numbers have now increased but it remains critically endangered. Popwood is related to our ngaio (Myoporum laetum). Photo by Sorrel Wilby via iNaturalist CC BY-NC 4.0
Tall tree trunks with young sprouting trunks growing beside it with leaves at the top.
Shade tree (Meryta latifolia). Only 33 plants were known in 1988 but this had increased to 149 plants by 2003. Shade tree is related to our puka/pukanui (Meryta sinclairii) from the Three Kings Islands, which is popular in New Zealand gardens. Photo by Lara Shepherd
Soft flax-like plant with a flowering stem with berries on it on the forest floor.
Dianella intermedia. This species is a relative of turutu or New Zealand blueberry (Dianella nigra). Photo by Lara Shepherd
Four green leaves in focus on a shrub.
Siah’s backbone (Streblus pendulinus). This species is a relative of New Zealand’s three milk tree species. It also occurs on other Pacific Islands and eastern Australia. The leaves are very rough and feel like sandpaper. Photo by Lara Shepherd
Close up of the leaves of a plant
Shade tree (Melicope littoralis). This species is endemic to Norfolk Island. It looks like a much larger version of New Zealand’s wharangi (Melicope ternata). Photo by Lara Shepherd
A shrub with many leaves and branches
Coprosma baueri. This endemic species looks very similar to our taupata (Coprosmsa repens). Photo by Lara Shepherd
Ground-level shrub with oval leaves and branches with nicks in the every centimetre or so.
Korthalsella disticha. This endemic mistletoe species is huge compared to the New Zealand species in this genus. Photo by Lara Shepherd
Two stems of a plant with wide green leaves on them. Photographed at night or in the shade.
Sharkwood (Didymocheton bijugus). The smell of this shrub after rain has been compared to that of a dead shark; hence its common name. It is a relative of our kohekohe (Didymocheton spectabile). Photo by Lara Shepherd
A tall flax-like plant that is tall as a tree. There is a man in a blue shirt standing on the right-hand side. He is about a fifth of the sixe of the plant.
Mountain rush (Freycinetia baueriana). This endemic species looks like our kiekie (Freycinetia banksii). It is currently considered to be critically endangered by the IUCN but we saw it in several places on the island. Photo by Lara Shepherd

The very different

Several other species that we saw looked quite different to any native New Zealand species.

View of a coastal beach with Norfolk Pine trees in the middle ground and low bush in the foreground.
A conifer rather than a flowering plant, the endemic Norfolk Is pine (Araucaria heterophylla) graces the Norfolk Island flag. It is a distant relative of kauri and is widely grown as a specimen tree in New Zealand, lining many coastal roads. Photo by Leon Perrie
Two pink flowers on the side of a bush.
White oak (Lagunaria patersonia subsp. patersonia). This subspecies also naturally occurs on Lord Howe Island and can grow into a large tree. It is a popular horticultural plant in New Zealand, where it is sold as Norfolk Island hibiscus. Photo by twan3253 via iNaturalist CC BY 4.0
A shrub with green leaves with orange berries.
Box (Alyxia gynopogon). Surprisingly, this small shrub is in the same family as our Parsonsia vines but the two genera look very different. Photo by suecar via iNaturalist CC BY-NC 4.0
Close-up of a flowering shrub. The four flowers are green with four petals each.
Kurryjunk/Kurrajong (Wikstroemia australis). Only 155 plants of this endemic species were known in 2003 but its numbers have since increased. It is a distant relative of New Zealand daphne (Pimelea). Photo by Lara Shepherd
A white flower with very long stamens shooting out.
Devil’s guts (Capparis nobilis). This endemic vine gets its name from the spines on the stem. Photo by Lara Shepherd
A rock with whit moss on it and leaves fanning out in random places.
Norfolk Island Oberonia (Oberonia titania). This tiny orchid perches on tree branches. It also occurs in Australia. Photo by Lara Shepherd
A close-up of pink flowers with one long stamen each.
Bastard oak (Ungeria floribunda) is a member of the hibiscus family. The single species in the genus is only found on Norfolk Island, making the entire genus endemic. It is related to the durian, infamous for the strong odour of its edible fruit. Photo by Peter de Lange via iNaturalist CC0 1.0.

Dangerous interlopers

Introduced weeds are a major threat to the native flora of Norfolk Island. There are almost twice as many introduced species as indigenous species!

A leafy forest floor with a lot of thin trees, some with leaves. There is a path in through the middle of it.
Strawberry guava/porpay (Psidium cattleyanum) is perhaps the worst weed on Norfolk Island. It naturally occurs in Brazil and was introduced to Norfolk Island in 1788 for its edible fruit. In some places in the National Park, there were dense stands of strawberry guava, with the ground thick with rotting fruit. Concerningly, we also saw strawberry guava seedlings in more undisturbed native forest. This species is considered one of 36 plant species on a list of the world’s 100 worst invasive alien species. Photo by Leon Perrie

Other common and widespread weeds were African olive (Olea europaea), lantana (Lantana camara) and Brazilian pepper (Schinus terebinthifolius). All three are also on the list of the world’s 100 worst invasive species.

A large covering of leafy vines spreading across part of a forest.
A large patch of lantana (Lantana camara) invading indigenous forest in Norfolk Island National Park. Photo by Lara Shepherd

We’re not innocent

There are also several weeds from New Zealand. For example, Kermadec pōhutukawa (Metrosideros kermadecensis) has been planted as shelter belts but has escaped cultivation. We saw it established at several areas around the coast. It is also a weed in Hawaii.

Harakeke (Phormium tenax) is another New Zealand species that occurs on Norfolk Island, where it is known as flax. The origins of this species, as well as its influence on early European settlement of the island, will be covered in another blog post.

1 Comment

  1. I’m a Horticulturalist living on Norfolk Island
    Thank you for this informative blog on the many lovely flora species of this magical piece of paradise in the Pacific.
    I feel blessed and privileged to call this place my home.

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