Australian Systematic Botany Australian Systematic Botany Society
Taxonomy, biogeography and evolution of plants

A taxonomic appraisal of the Chatham Islands flax (Phormium tenax) using morphological and DNA fingerprint data

R. D. Smissen A B and P. B. Heenan A
+ Author Affiliations
- Author Affiliations

A Allan Herbarium, Landcare Research, PO Box 40, Lincoln 7640, New Zealand.

B Corresponding author. Email:

Australian Systematic Botany 23(5) 371-380
Submitted: 8 June 2010  Accepted: 28 July 2010   Published: 3 November 2010


A range of leaf forms of Phormium tenax J.R.Forst. & G.Forst. can be observed in the wild on the Chatham Island archipelago. At one extreme are plants with more or less upright leaves, similar to those observed in New Zealand P. tenax, and at the other extreme there are plants with floppy leaves. The upright-leaved form is found more or less throughout the archipelago, whereas the floppy-leaved form is concentrated in the southern part of Chatham Island, Pitt Island, and on the other southern islands (e.g. South East and Mangere islands). Analysis of amplified fragment length polymorphism (AFLP) and simple-sequence-repeat (SSR) variation, and comparison with a diverse sampling of New Zealand Phormium suggested that both Chatham Islands forms are indigenous and part of a common gene pool. We found no evidence of hybridism with Phormium introduced from New Zealand. Floppy-leaved forms are therefore linked to typical upright leaved P. tenax through upright-leaved plants with bent tips, and do not require taxonomic recognition. AFLP and SSR data both support the view that a plant collected from Ranui Cove, Auckland Island, is descended from Chatham Islands material, and was most likely introduced there by Ngāti Mutunga and Moriori settlers during the 19th century.


The authors acknowledge Peter de Lange and Amanda Baird (Department of Conservation) for invaluable assistance in the collection of Chatham Islands samples, and Katarina Tawiri as kaitiaki of the National New Zealand Flax collection. Nic Bolstridge, Molecular Laboratory Manager, Landcare Research, provided technical support. We also acknowledge Leon Perrie, Geoff Walls, Peter de Lange, and Sue Scheele for helpful discussion on the Chatham Islands Phormium and Chatham Islands flora generally. This paper benefitted from review by Sue Scheele, Peter de Lange and Christine Bezar. This research was supported by funding from the Foundation for Research, Science and Technology through the Defining New Zealand’s Terrestrial Biota OBI.


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