1. How many indigenous plants are there in New Zealand?
The number of indigenous plants in New Zealand which have been formerly named is as follows:
Vascular plants: 2,522
Mosses: approx. 560
Liverworts: approx. 600 (likely to be 1000)
Macroalgae (seaweeds): approx. 800 (likely to be 1000)
Please note that the estimated number of plants changes as scientists find, name or reassess the taxonomic status of plants.
2. How many plants are there in the world?
There are an estimated 422,000 flowering plants in the world, approximately 1,000 gymnosperms, 15,000 ferns and fern allies (including club mosses, spike mosses, quillworts, spike horsetails and whisk ferns) and approximately 22,000 mosses, liverworts and hornworts.
3. How many exotic plants occur in New Zealand and how many of these are weeds?
There are 24,744 exotic species recorded in NZ according to Duncan & Williams (2002)*. Some experts estimate that the number may be more like 35,000 although there is no definitive list. The NZPCN website lists 2,684 of these exotic plants as naturalised in New Zealand. Of these, approximately 300 to 500 are regarded as serious environmental weeds.
* From: Duncan, R.P.; Williams, P.A. (2002) Darwin’s naturalization hypothesis challenged. Nature 417: 608-609.
4. What is the difference between a weed, an alien plant, a naturalised plant, an adventive and a non-native?
A weed is a plant that grows in the wild and which is negatively affecting things we value (e.g., the natural environment, our health or our livelihoods). A weed is often also referred to as an invasive plant. An alien plant is one which does not naturally occur in a certain place (i.e., it is not native) but may or may not be not established in the wild. Alien plants are also referred to as adventive, casual, or non-native. A naturalised plant is one not native but which is established, or grows and reproduces, in the wild (some adventive species have become problematic and may also be considered weeds).
5. How many threatened plants are there in New Zealand and in the world?
Over 15% of New Zealand’s indigenous plants are regarded as threatened and a further 31% are At Risk in New Zealand. The IUCN (World Conservation Union) Red List for the planet contains 8,447 plants in 2007 and is regularly reassed.
6. What is the difference between a rare, threatened or endangered plant?
A rare plant is one that is not commonly found in the wild. It may be naturally rare or sparse or may have a restricted range. Rare plants may or may not be of conservation concern. A threatened plant is a rare plant which is at risk of extinction in the wild. An endangered plant is a type of threatened plant. It is a technical term for describing the degree of risk of extinction a plant is under. Some technical terms, such as endangered, are commonly and inaccurately used to refer to all threatened plants.
7. Who decides which plants in NZ are listed as threatened?
In conjunction with the Department of Conservation, the Network is involved with a 5 yearly assessment of the status of New Zealand’s threatened plants. Information collated is assessed by an expert panel comprising Peter de Lange, John Barkla, David Norton, Ewen Cameron, Peter Heenan, Shannel Courtney and Andrew Townsend (facilitator). Each new threatened plant list is published in the New Zealand Journal of Botany.
8. How many plant species are endemic to New Zealand?
There are an estimated 1,984 species, subspecies, varieties or forms that are endemic to New Zealand which is 82.2% of the New Zealand flora. These plants cannot be found growing naturally in the wild outside of New Zealand. This high degree of endemism is one of the reasons for New Zealand being identified by Conservation International as a Centre of Plant Diversity and world biodiversity hotspot.
9. What does endemic mean?
Endemic means exclusively native to the biota of a specific place. A species that is endemic is unique to its own place or region: found only there, and not found naturally anywhere else.
10. Are there any plant families endemic to New Zealand?
Ixerba used to be the only endemic flowering plant family in New Zealand until the APG merged the Ixerbaceae with the New Caledonian Strasburgiaceae. There is only one NZ species in this family - Ixerba brexioides
11. What is a divaricating plant?
New Zealand has more than 60 species of small-leaved shrubs and low-growing trees with densely interlaced wiry, highly tensile stems. Collectively these are known as divaricating shrubs because their branches are spread apart at a wide angle. The divaricating form is also referred to as filiramulate meaning plants that have small widely spaced leaves or short shoots on thin, often tough branches and are a characteristic feature of over 60 species the New Zealand flora. They include conifers, daisies, myrtles, brooms, pittosporums, and coprosmas. This feature is found elsewhere but is most prominent in New Zealand, where it occurs in around 10% of woody plants and has evolved independently in 18 plant families. Examples of species are: Corokia cotoneaster,Raukaua (Pseudopanax) anomalum, Elaeocarpus hookerianus.
12. What is a hybrid?
A hybrid is an organism that is the offspring of genetically dissimilar parents or stock; especially offspring produced by breeding plants or animals of different varieties or breeds or species. For plants that means it has parents which are genetically distinct (different cultivars, varieties, species or genera). Hybrids can occur naturally in the wild or be artificially crossed by a plant breeder. Hybrids in garden centres have usually been crossed to achieve a desired outcome such as a showy flower, coloured foliage or a more hardy plant.
An example from the New Zealand flora is the sterile Thelymitra xdentata (a sporadically occurring hybrid between Thelymitra longifolia and Thelymitra pulchella). Click here to read the Network fact sheet.
13. What is a cultivar?
While a hybrid (see above) is usually a cultivar (CULTIvated VARiety), a cultivar is not necessarily a hybrid. A cultivar is a plant selected for its commercial qualities. It may be an unusual one-off wild form or it may be an unusual form selected in a nursery, or a hybrid.
14. How can I tell whether a plant is wild, or is a hybrid or a cultivar?
Plant names can help distinguish between a wild plant, a hybrid or a cultivar. Every wild plant a scientific name in Latin composed of two parts: 1) the genus name, and 2) the species name. The genus is a bit like a surname, and the species a given name. There may also be a variety or form name, both also in Latin. Usually a cultivar has a non-Latin name which is often in single inverted commas e.g. Phormium ‘Yellow Sun’, or Griselinia littoralis ‘Eden Mint’.
The name of a hybrid usally has an x (the multiplication sign) in it symbolizing it is a cross e.g., Coprosma propinqua x robusta. However, a hybrid bred to be sold in a nursery can also have a cultivar name.
15. What indigenous woody plants are deciduous (i.e., shed leaves at the end of the growing season)? Are there any deciduous trees native to NZ?
See the Deciduous plant section of this website for a list of deciduous species. Approximately 28 species (4.8%) of the New Zealand woody flora have a marked loss of leaves in winter. Only 11 species are consistently fully winter deciduous (adults are entirely leafless, or nearly so, towards the end of winter) although juvenile plants in some populations may retain significant foliage during the winter. Some species show stronger decidous behaviour at higher altitude or higher latitudes.
Some populations of Sophora microphylla and Sophora tetraptera are brevideciduous meaning they lose their overwintering leaves in spring at the time of flowering and before the new leaves have flushed, but are otherwise annual evergreens.
Coriaria angustissima, C. plumosa, C. pottsiana, and C. sarmentosa are rhizomatous subshrubs in which the above-ground stem and leaves die back completely in winter. They are rarely included in lists of indigenous deciduous trees and shrubs because they have a herblike appearance. However, they have woody rootstocks and should be regarded as deciduous.
For more information about deciduous trees see:
McGlone et al. 2004. Winter leaf loss in the New Zealand woody flora. New Zealand Journal of Botany, 2004, Vol. 42: 1-19.
16. Are there poisonous indigenous plants? Which are the most poisonous?
There are only a very few native plants in NZ poisonous to humans and/or stock. There are far more poisonous exotic plants in gardens and naturalised in the wild. See the Poisonous plants section of this website.
Poisonous native plants include: karaka (Corynocarpus laevigatus), kōwhai (Sophora species), tītoki (Alectryon excelsus), ngaio (Myoporum laetum) poroporo (Solanum aviculare and Solanum laciniatum), tūrutu (Dianella nigra), New Zealand daphne (Pimelea prostrata), tutu (Coriaria species), waoriki (Ranunculus amphitrichus), ongaonga (Urtica ferox), and bracken fern (Pteridium esculentum). For more information see the Poisonous native plants section fo this website.
* Connor, H. E. 1951. The Poisonous Plants in New Zealand. New Zealand D.S.I.R. Bulletin: 99.
17. What is New Zealand’s tallest tree?
Kahikatea (Dacrycarpus dacrydioides) is New Zealand’s tallest indigenous tree. This is a distinctive tree of usually swampy alluvial terraces. Its main habitat is lowland forest. It was formerly dominant on frequently flooded, and/or poorly drained alluvial soils. Occasionally extends into lower montane forest. Once the dominant tree of a distinct swamp forest type all but extinct in the North Island - the best examples remain on the West Coast of the South Island.
18. What is New Zealand’s smallest plant?
New Zealand’s smallest vascular plant is Water meal (Wolffia australiana) a minute aquatic plant.
Other tiny plants are the pygmy orchid (Ichthyostomum pygmaeum) which grows epiphytically on tree trunks, iti (Cardamine lacustris), the forget-me-nots (Myosotis brevisand M. pygmaea), Gentiana lilliputiana, several pygmy weeds (Crassula species), Petrie’s starwort (Callitriche petriei subsp. petriei), and Stackhousia minima. The smallest grass is pincushion grass Agrostis muscosa and the smallest sedge, at only 6mm tall, is Isolepis basilaris. Most of New Zealand’s non-vascular plants are tiny, and some are only visible with a hand lens.
19. Which of New Zealand’s plants produces the most nectar?
The male inflorescences of Dactylanthus taylorii each contain up to 1.6 ml of nectar (Ecroyd 1996). The nectar in dactylanthus flowers attracts its pollinator, the short-tailed bat.
20. What is New Zealand’s rarest tree?
According to the Guiness Book of Records, one of the rarest trees in the world is New Zealand’s Pennantia baylisiana with just one specimen growing in the wild. The species was discovered by Geoffrey Baylis on the Great Island of the Three Kings Group in 1945. Baylis took a cutting that he grew in Dunedin, and since then other trees have been cultivated in gardens. It has large glossy leaves, and looks rather like a karaka. There is still just this single tree growing wild on the Three Kings.
22. Where should I go to see native plants?
To see native plants near to towns or cities visit your local botanic gardens or specialist native plant nursery. These places label their plants so you can learn their names. You can also visit your local herbarium to view pressed specimens. Ask your local or regional council if they manage a reserve with an interpretive, labelled, walk. There are also reserves, national parks and conservation areas throughout the country managed by the Department of Conservation. Contact your local Department of Conservation office for more information or visit their website.
23. Are any indigenous plants pollinated by lizards?
Geckos visit flowers of several native plant species for nectar and pollen (e.g., pohutukawa and flax). New Zealand herpetologist Tony Whitaker has also shown that both skinks and geckos are also seed dispersers of many native New Zealand plants. Today the lizard fauna has declined so much that lizard and plant interactions are now only easily observed on predator free offshore islands.
24. Are there any parasitic plants indigenous to NZ?
New Zealand has only one fully parasitic flowering plant, Dactylanthus taylorii, which grows under the ground attached to the roots of a host tree. It takes all its sustenance from its host. New Zealand also has eight mistletoes which are stem hemi-parasites. They have green leaves and make their own food through photosynthesis but use a host tree or shrub to obtain water.
25. Does New Zealand have any indigenous orchids?
New Zealand has 117 described species of orchids in 24 genera. Orchids are highly represented in threatened plant categories as they are vulnerable to habitat loss e.g., clearing of scrub and draining of wetlands. View the Orchid section of this website for more infromation.
26. Are mangroves native to NZ?
New Zealand’s has only one mangrove, Avicennia marina subsp. australasica. This is the most southerly growing mangrove in the world. This sub-species is native to New Zealand, but is also found naturally in south-eastern Australia and Lord Howe Island.
27. Will any threatened NZ plants be affected by climate change?
Climate change is likely to have a diverse range of impacts on New Zealand’s flora either directly by creating conditions not conducive to survival and reproduction or exacerbating impacts of invasive species. Plants at their distributional limits, or higher altitudes, may be more affected and coastal species will be ‘squeezed’ between rising sea levels and modified inshore habitats. Understanding the ecology of threatened plants is a key requirement to managing populations in the light of climate change. Seed banking is a ‘worst case scenario’ insurance scheme to help plants re-establish if they become extinct in the wild, however not all plants can be banked and there is much work to do in collecting and storing specimens. Follow this link to learn more about seed banking in New Zealand.
28. Are kauri trees rare?
Kauri (Agathis australis) have become rare due to historic logging and have recently been re-assessed as Tthreatened - Nationally Vulnerable due to the novel threat of kauri dieback disease (Phytophthora taxon Agathis or PTA). Some stands of kauri on private land remain vulnerable to illegal logging, while trees are still periodically removed (although only by permit or with approval) for cultural purposes, such as for making waka (canoes) or other Maori buildings and structures. Some small southerly populations are rather vulnerable to goat browse destroying regenerating seedlings and saplings. For more information about kauri read the Network fact sheet.
29. What is the difference between pampas and the native toetoe?
Native toetoe was once included in the same genus as the South American species of pampas (Cortaderia sp.), however native toetoe species are now included in the genus Austroderia. Toetoe species are easily distinguished from pampas species by their spring-flowering, rather than autumn flowering habit, waxy leaf sheaths, and by the dead leaves which fold longitudinally and separate at the joints. In contrast, the flowers of pampas are stout, erect, densely feather-like flower head, and ivory leaf sheaths. Pampas leaves curl up toward the leaf base, ultimately decaying to a state resembling wood shavings. Note, there are four species of toetoe, though garden centres and nurseries often only sell the North Island species (Cortaderia toetoe). Care should be taken to ensure the correct local species is used in restoration plantings, and material is gathered from naturally occurring populations and not gardens or roadside plantings.