‘Punga’ is a quintessential Kiwi word used to refer to tree ferns or sometimes, more specifically, the trunks of tree ferns.
But in his book A Dictionary of Maori Plant Names, James Beever does not record any tree ferns as being called punga by Māori. I don’t know for sure, but I suspect that ‘punga’ is an English corruption of ponga. Does anyone know otherwise?
Ponga is the silver fern Cyathea dealbata, which is a real plant and not just a marketing creation! Adult ponga are immediately recognisable by the white undersides of their fronds, and they can be identified even at a distance by the white tinge of their fronds’ stems.
There are two main groups of tree ferns: Cyathea and Dicksonia. They are easily distinguished since the former is scaly and the latter is hairy.
Besides ponga, the other prominent Cyathea in New Zealand are mamaku and kātote. Mamaku, or Cyathea medullaris, is our tallest tree fern, with thick, black frond stems, and it is a common coloniser of hillside slips.
Te Papa has a specimen of mamaku collected in 1769 during Captain Cook’s first expedition.
Kātote, or Cyathea smithii, is recognised by its retention of dead frond stems as a ‘skirt’. It is more common in colder habitats.
Whekī (pronounced ‘fare-key’, with emphasis on the ‘e’ sound in ‘key’) and whekī-ponga are the prominent Dicksonia species in New Zealand. Whekī-ponga, or Dicksonia fibrosa, retains a skirt of dead fronds, and its trunk can reach a comparatively massive girth.
Whekī, or Dicksonia squarrosa, is commonly found around streams and other wet areas. Even as young plants, whekī and whekī-ponga can be easily distinguished by the colour of their fronds’ stems, which are brown and green respectively. Whekī forms buds on its trunk, and it can resprout if the main crown is damaged – or if the fronds and roots are cut off and the trunk is used to make a fence!
Many pungas for sale are not actually ponga but whekī. If you want to make a wall of tree fern trunks that has a reasonable chance of coming back to life, ask for whekī.
All of New Zealand’s tree ferns are described and illustrated in the book New Zealand Ferns and Allied Plants, by Patrick Brownsey and John Smith-Dodsworth.