| Silver fern | |
|---|---|
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| Frond, showing the silver-white underside | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Cyatheales |
| Family: | Cyatheaceae |
| Genus: | Alsophila |
| Species: | A. dealbata |
| Binomial name | |
| Alsophila dealbata | |
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| Synonyms | |
| |
Alsophila dealbata (synonymsAlsophila tricolor andCyathea dealbata), commonly known as thesilver fern[2] orsilver tree-fern,[3] or asponga/ˈpɒŋə/ orpunga/ˈpʌŋə/ (fromMāorikaponga orponga), is a species of medium-sizedtree fern,endemic to New Zealand. The fern is usually recognisable by the silver-white colour of the under-surface of maturefronds. It is a symbol commonly associated with the country both overseas and byNew Zealanders themselves.
This fern is known to grow to heights of 10 metres (33 ft) or more (though it occasionally takes a rare creeping form).[4] The crown is dense, and mature fronds can be as much as 3 metres (9.8 ft) long and 1 m (3 ft 3 in) wide with a silver-white colouration on the undersides. The fronds may bebipinnately compound ortripinnate. The underside colouration is less intensely silvery or patchy in younger plants and juveniles are pale green.[5] This distinctive silver colouration has made them useful for laying along tracks for night walking. The scales are a dark brown and are often twisted and glossy.[4]Rhizomes very rarely prostrate, usually erect, forming a woody trunk up to 12 metres (39 ft) tall, 160 to 450 millimetres (6.3 to 17.7 in) in diameter, covered in light brown or white projecting stipe bases, bearing scales near the apex.[6]
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The species was first formally described in 1786 by German naturalistGeorg Forster in the bookFlorulae Insularum Australium Prodromus, who used the namePolypodium dealbatum.[7] The species was moved to the genusCyathea byOlof Swartz in 1801, leading to the scientific nameCyathea dealbata.[8] The species was moved to the genusAlsophila in 1970 byRolla M. Tryon Jr., who used the nameAlsophila tricolor, citingWilliam Colenso's 1883 description ofCyathea tricolor, which Colenso believed was a species distinct fromCyathea dealbata.[9][10]
The current preferred scientific name is disputed, withPlants of the World Online,New Zealand Plant Conservation Network, and the Synonymic Checklist and Distribution of Ferns and Lycophytes of the World Version 25.06 preferringAlsophila dealbata,[11][12][13]Manaaki Whenua – Landcare Research preferringCyathea dealbata[14] andWorld Flora Online preferringAlsophila tricolor.[15] The nameAlsophila tricolor was considered the correct scientific name for the species, due to the species epithetdealbata being preoccupied in the genus by a species described in 1848 byCarl Borivoj Presl, now considered a synonym ofSphaeropteris glauca. In 2025 it was shown that the silver fern has priority to use this name over the species Presl described, due to a reference made byAugust Carl Joseph Corda to the species in 1838, making Presl's use an illegitimate later homonym.[12]
The species epithetdealbata means whitish, and refers to the underside of the fronds.[16] The Māori wordponga, pronounced[ˈpɔŋa], is a term used acrossPolynesian languages to describe tree ferns,[16] such asSphaeropteris lunulata inTongan andSamoan orAngiopteris evecta in Samoan.[17] It has been borrowed into New Zealand English using both the spelling ponga and punga,[16] and is used as a generic term for tree ferns, and to refer to tree fern logs when used for landscaping purposes.[citation needed] English speakers generally pronounce the word/ˈpʌŋə/PUNG-ə.[citation needed] Other Māori language names for the plant include kaponga, kātote,[18] or poka insouthern dialects.[19]
Arriving relatively late in New Zealand's history during thePliocene epoch[20] (around 5.0–1.8 million years ago), the silver fern occurs on the main islands of New Zealand—although absent from the west and south regions of the South Island,[21] on theChatham Islands to the east, and is also native toLord Howe Island.[1] It has also becomenaturalised in Ireland.[22] Its primary habitat is subcanopy areas of drier forests and in open scrub, although it is occasionally found on bush margins and in more open areas, and has been recorded from amongst rushes in a dune slack.
The fern is known to grow well in well-drainedhumus, and once established, it will tolerate drier conditions.[23] It does best when sheltered from winds and should be protected from frost. Evidence of large amount of macro-charcoals in the top layers of soil suggest thatAlsophila tricolor establishes itself in areas where anthropogenic fires occur.
In traditionalMāori culture, ponga is seen as a symbol new life and growth. Ponga trunks were often used in the construction ofwhare, walls and palisades.[16] Thekoru symbol, which depicts the shape of an unfurling silver fern frond, is found extensively in Māori art, including in designs of carvings,marae andtā moko,[16][24] Pūrākau (traditional stories) involve the silver fern once living in the sea, and that hunters at night time would use the white underside of fern fronds to mark a path home in the darkness, as the undersides could easily catch moonlight.[25][16]
Ponga logs are widely used in landscaping in New Zealand, used to create retaining walls and edging for gardens.[16]
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The silver fern is one of the most widely recognised symbols of New Zealand.[16][26] The first use of the silver fern as a symbol representing New Zealand was during the1888–89 New Zealand Native football team tour of Britain,[27] after which the symbol came to be used on dairy products exported from New Zealand to the United Kingdom.[16]
The silver fern was used as an identified by the New Zealand Army during theSecond Boer War. Since then, the silver fern has been used by theNew Zealand Expeditionary Force during both world wars, and all Commonwealth war graves of fallen New Zealand soldiers have the silver fern engraved on their tombstones.[21] During the1956 Suez Crisis, Egyptians took exception to New Zealand and Canadian peacekeepers having theUnion Flag on their uniforms. Canadian troops wore theMaple Leaf whereas the New Zealand contingent wore a silver fern symbol. New Zealand peacekeepers have since used both the silver fern andkiwi symbols for different deployments to differentiate from their Australian and British counterparts.[citation needed] Additionally, severalBritish Army units wear the silver fern, normally as a battle honour granted for serving with New Zealand troops. For example, theQueen’s Royal Hussars, theRoyal Wiltshire Yeomanry and theWarwickshire Yeomanry, all of whom fought with2nd New Zealand Division at theSecond Battle of El Alamein.
The silver fern has long been used on dairy products, including the logo ofNew Zealand Natural, and was trademarked as early as 1885.[citation needed] It is a logo for many other organisations, such as (heavily stylised) the rail operatorKiwiRail. TheSilver Fern is also the name of a class ofrailcar.[28]
Silver fern fronds appear on thecoat of arms of New Zealand.[29] Some alternativeflags for New Zealand, such as thesilver fern flag, utilise the fern. The official proposal of the2015–2016 New Zealand flag referendums featured the silver fern.[30] The silver fern is also used extensively within politics and printed material, such as the logo of theNew Zealand Labour Party.[31]
Thekoru is part of the design of theMāori flag, and is used in a stylised form as the logo for national airlineAir New Zealand.[32] Its circular shape conveys the idea of perpetual movement, and its inward coil suggests a return to the point of origin.[24]
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The silver fern has been used as a symbol by New Zealand national sports teams, in various stylised forms, since it was first worn by players in the1888–89 New Zealand Native football team which toured Britain.[27] "Silver Ferns" is the name of thenational netball team, and most other national women's sports teams have nicknames based on the term "Ferns", such asBlack Ferns (women's rugby union),Tall Ferns (women's basketball) andFootball Ferns (women's association football).[26]
National sport teams using the silver fern include:
The silver fern is also extensively used as part of the official symbols ofNew Zealand Olympics teams.[33]
In 1991, theNew Zealand Rugby Football Union obtained trade marks for the name "All Blacks" and its own stylised fern, however the scope of the application was broader because they sought to register any 'fern'. In 2005, after a legal case lasting four years, the union failed in its bid to stop anyone else using any fern logo on any black jersey.[34]
