silver fern, ponga
Alsophila tricolor (Colenso) R.M.Tryon; Cyathea dealbata var. tricolor (Colenso) Domin; Cyathea tricolor Colenso; Polypodium dealbatum G.Forst.
Vascular – Native
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
2n = 138, 144
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
Tree fern with green-stalked soft leaves to 4m long that are distinctly silver on the underside. Trunk to 10m tall, covered by the bases of old fronds. Leaf stems covered in wavy hairs (lens needed). Sporangia arranged in small round capsules underneath leaves.
Endemic. From the Three Kings Islands south to Mahers Swamp in the west and Dunedin in the east of the South Island.
Common, primarily coastal and lowland habitats but extending to lower montane. Preferring dry forest and shrubland, often under pines.
Tree fern up to 10 m tall (very rarely without trunk). Trunk covered in long-persistent, peg-like, stipe bases. Stipes slender, silvery-white when young, maturing pale brown. Harsh to the touch, covered in pale-brown scales. Scales without marginal spines. Fronds up to 4 m long, horizontal, somewhat arching, 3-pinnate. Dead fronds falling. Longest primary pinnae 300-550 mm, pale green above, white below (very rarely pale green) below. Under surfaces sparingly clad in curly hairs. Indusia covering sori at maturity, opening at maturity to form a deep cup with a smooth rim.
Distinctive. Could only be confused with the Raoul Island (Kermadec Island Group) endemic Cyathea milnei which is occasionally cultivated on the New Zealand mainland. C. milnei is easily recognised by the pale green rather than white frond under surfaces, and by the persistent skirt of dead fronds. It is rather cold sensitive. Some populations of Cyathea dealbata at Te Paki are distinctive because their fronds have pale grey rather than silvery white under sides and often these plants have a creeping, trunk less (or nearly trunk less) habit. Their status needs further investigation, especially as this form can be found at Te Paki growing alongside Cyathea dealbata plants with a well defined trunk and silvery-white frond under sides. The Te Paki form retains its trunk less (or short trunk) and pale grey frond undersides in cultivation. It is very slow growing.
None (spore bearing)
None (spore bearing)
Can be grown from fresh spores (but slow). Young plants transplant easily and freshly felled trunks will usually resprout if planted and carefully watered. Easy, once established in a varieity of conditions. Should not be removed from the wild unless with the landowners permission.
cyathea: From the Greek kyatheion ‘little cup’, referring to the shape of the indusium
Where To Buy
Sold by most commericial nurseries. Commonly cultivated.
Fact sheet prepared for NZPCN by P.J. de Lange March 2004. Description adapted from Brownsey & Smith-Dodsworth (2000).
References and further reading
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand Ferns and Allied Plants. Auckland, David Bateman
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Cyathea dealbata Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/cyathea-dealbata/ (Date website was queried)