Species

Cyathea dealbata

Etymology

Cyathea: From the Greek kyatheion 'little cup', referring to the shape of the indusium
dealbata: whitened

Common Name(s)

silver fern, ponga

Current Conservation Status

2012 - Not Threatened

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Cyathea dealbata (G.Forst.) Sw.

Family

Cyatheaceae

Brief Description

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.

Flora Category

Vascular - Native

NVS Species Code

CYADEA

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.

Structural Class

Ferns

Synonyms

Alsophila tricolor (Colenso) R.M.Tryon; Cyathea dealbata var. tricolor (Colenso) Domin; Cyathea tricolor Colenso; Polypodium dealbatum G.Forst.

Distribution

Endemic. From the Three Kings Islands south to Mahers Swamp in the west and Dunedin in the east of the South Island.

Habitat

Common, primarily coastal and lowland habitats but extending to lower montane. Preferring dry forest and shrubland, often under pines.

Features

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.

Similar Taxa

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.

Flowering

None (spore bearing)

Flower Colours

No Flowers

Fruiting

None (spore bearing)

Propagation Technique

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.

Threats

Not Threatened.

Chromosome No.

2n = 138, 144

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Where To Buy

Sold by most commericial nurseries. Commonly cultivated.

Attribution

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

 

This page last updated on 30 Dec 2014