Species

Cyathea milnei

Etymology

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

Common Name(s)

Milnes tree fern

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - At Risk - Naturally Uncommon
2004 - Range Restricted

Qualifiers

2012 - IE, OL
2009 - IE

Authority

Cyathea milnei Hook.f.

Family

Cyatheaceae

Brief Description

Tree fern with brownish-stalked soft leaves to 4m long inhabiting Raoul Island in the Kermadec Islands. Trunk to 8m tall, skirted by remains of old fronds. Leaf stems covered in wavy hairs (lens needed). Sporangia arranged in small small deep cups underneath fronds.

Flora Category

Vascular - Native

NVS Species Code

CYAMIL

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 milnei (Hook.f.) R.M.Tryon

Distribution

Endemic. Kermadec Island group, Raoul Island only

Habitat

Most commonly found in the lower altitude, drier forested parts of Raoul Island. However, occasional plants are found also in the wetter, higher altitude forest.

Features

Tree fern up to 10 m tall. Trunk scaly, bearing numerous stub like, projecting stipe remnants. Stipes stout, initially evenly yellow, maturing pale brown, rugose, basally covered with persistent scales (usually with sparse caducous scales running along sides of the upper stipe and rachis); scales dark brown lacking marginal spines. Fronds up to 4 x 2 m, bright yellow green to somewhat milky-green above, paler beneath, held horizontally, 3-pinnate, coriaceous; dead fronds long persistent, forming a dense skirt around trunk. Primary pinnae up to 450 mm long, undersides bearing fine curly hairs. Indusia covering mature sori, opening to form a deep, cupular structure with a smooth rim. Description adapted from Brownsey & Smith-Dodsworth (2000).

Similar Taxa

On Raoul this species is sympatric with C. kermadecensis W.R.B.Oliv. from which it differs by its smaller stature ( up to 10 cf 20 m in C. kermadecensis), scaly rather than scaly and hairy stipes, horizontal rather than arching fronds which are retained rather than dropping when dead to form a skirt and pinnae undersides which have fine curly scales rather than scales whose apices are terminated by single or stellate spines. Cyathea milnei is very similar to C. dealbata (G.Forst.) Sw. which is endemic to New Zealand proper. It is easily distinguished from that species by the pale brown rather than silver stipe and rachis, and pale green rather than silvery-white colour of the pinnae undersides. However, in Te Paki some populations of C. dealbata lack this colouration, and appear to be very similar to C. milnei - these plants require further study.

Flowering

Not applicable - spore producing

Flower Colours

No Flowers

Fruiting

Not applicable - spore producing

Propagation Technique

Easily grown from spores. Initially plants are cold and drought sensitive. However once established this species is very fast growing. It prefers semi-shade in a warm, sheltered site. It should be planted in a free draining, moist soil. Once established it can tolerant drought but it should not be allowed to dry out for too long. Although more cold tolerant that C. kermadecensis W.R.B.Oliv. it is best grown in warmer climates.

Threats

Not Threatened. Listed because it is a narrow range endemic naturally confined to Raoul Island. On this island it is abundant.

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Where To Buy

Occasionally available from specialist native and general plant nurseries

Attribution

Fact sheet prepared for NZPCN by P.J. de Lange July 2009. 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