Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Indigenous plants

New Zealand´s flora is still not fully understood. It is estimated that between 15 and 20% of the vascular plant flora of New Zealand remains unnamed.

Celmisia sessiliflora

Celmisia sessiliflora

Research in this area aims to investigate a number of problematic genera. Genera such as Cardamine, Craspedia, and Myosotis probably contain large numbers of unnamed species; these genera require detailed research to understand relationships and variation in the genus.  We also study genera with fewer species or smaller and more easily defined taxonomic issues that can be resolved without having to undertake a major study of the whole genus. Since 1995 research has addressed many of these smaller taxonomic problems in the indigenous and naturalised flora.

Research may include detailed morphological, anatomical, chemical and molecular investigation. It involves extensive fieldwork and growing plants in uniform conditions in cultivation to fully understand the variation in the group. The resulting monographs provide comprehensive description of the taxa in New Zealand including identification keys and detailed description, synonymy and analyses of taxa and their variation.

Why does New Zealand have so many indigenous species?

New Zealand is renowned for its exceptional ecological richness and disharmonic biota, which may have been brought about by its long isolation, the great range in altitude and rainfall, and its diverse landforms, rocks, and soils.

Following the separation from Australia, New Zealand drifted northwards into warmer climates but remained close enough to other land masses such as New Caledonia to gain new plants by long– distance dispersal. A distinctive tropical, woody element of New Zealand’s flora can be traced to this period. Many of its members, including palms, pittosporums, coprosmas and araliads, adapted to cooler climates or survived the following cool periods only in the far north. Beginning 10 million years ago, movement of the two continental plates thrust up tall mountain chains, thus creating new alpine habitats. There is much debate over the origin of our alpine flora. Undoubtedly, some plants already in New Zealand adapted to the new alpine areas whereas others arrived from or via Australia or Antarctica. The Apiaceae, Asteraceae, Plantaginaceae, and other families rapidly diversified in the alpine zone. Dispersal of plants to New Zealand by strong westerly winds, by floating in seawater, or on the feet of waterbirds still provides a continual supply of new species.

Features of New Zealand flora

New Zealand’s flora shows many unusual features. For example, New Zealand has a high proportion of plants that have separate male and female individuals (Webb et al. 1999) and New Zealand has become a centre for research in plant sexuality. Godley (1975, 1979) showed that a high proportion of this gender dimorphism had probably not evolved in New Zealand, leading Lloyd (1985) to propose that immigrant selection was involved in about 85% of the examples of the evolution of New Zealand’s unisexual plant groups.

Compared with their overseas relatives, the flowers of native plants are often small, white, and regular, with short tubes and spreading petals. Such simple flowers are hypothesised to suit New Zealand’s pollinating insects (Lloyd 1985). In some seed plant families the ancestors of today’s natives probably had simple flowers when they arrived in New Zealand enabling these plants to diversify rapidly here. In other groups, e.g. Melicytus (Powlesland 1984), ancestors of New Zealand’s simple–flowered species lost their complex pollination mechanisms during later evolution in New Zealand (Newstrom & Robertson 2005).

Some families have shown a remarkable adaptability in evolving forms to cope with new habitats. This is particularly true of New Zealand’s alpine cushion plants, mountain scree plants, and lowland divaricating shrubs. New Zealand’s flora has few annuals, deciduous plants or geophytes, and this is thought to result from an equable and unpredictable climate (Godley 1975). The absence of the scleromorphic element so characteristic of Australia is thought to be a result of higher soil fertilities in New Zealand’s rapidly eroding landscapes (Flannery 1994; Groves 1994), which place slow–growing scleromorphic immigrants at a disadvantage in competition with mesomorphic species (Lloyd 1985).


  • Houliston GJ, Dawson MI, de Lange PJ, Heenan PB 2012. Using AFLP markers to inform population management of the endemic Chatham Island toetoe, 'Austroderia turbaria' (poaceae). Pacific conservation biology 18(1): 33-40.
  • Heenan PB 2011. Gender dimorphism in Pachycladon stellatum (Brassicaceae). New Zealand Journal of Botany 50(1): 77-81.
  • Heenan PB 2011. Taxonomic notes on the New Zealand flora : Hypericum gramineum and Hypericum involutum (Hypericaceae). New Zealand journal of botany 49(1): 133-139.
  • Heenan PB, de Lange PJ 2011. Myoporum semotum (Scrophulariaceae), a new tree species from the Chatham Islands, New Zealand. New Zealand journal of botany 49(1): 17-26.
  • Mirzaei M, Pascovici D, Keighley T, George I, Voelckel C, Heenan PB, Haynes PA 2011. Shotgun proteomic profiling of five species of New Zealand Pachycladon. Proteomics 11(1): 166-171.
  • Smissen RD, Heenan PB 2011. Interspecific hybridization among indigenous New Zealand Convolvulus (Convolvulaceae) and the affinities of the Awahokomo limestone population. New Zealand Journal of Botany 49(3): 329-338. <Go to ISI>://CABI:20113347482
  • Yogeeswaran K, Voelckel C, Joly S, Heenan PB 2011. Pachycladon. 14 14 In: Kole ed. Wild Crop Relatives: Genomic and Breeding Resources. Tokyo, Springer-Verlag. Pp. 227-249.
  • Breitwieser I, Ford KA, Smissen RD 2010. A test of reproductive isolation among three sympatric putative species of Craspedia (Asteraceae : Gnaphalieae) at Mt Arthur in New Zealand. New Zealand journal of botany 48(2): 75-81.
  • de Lange P, Heenan P, Norton D, Rolfe J, Sawyer J 2010. Threatened plants of New Zealand. Christchurch, Canterbury University Press. 471 p.
  • Heenan PB, Sykes WR 2010. Taxonomic notes on the New Zealand flora : xCarpophyma mutabilis and xCarpophyma pallida (Aizoaceae), new names for two wild intergeneric hybrids. New Zealand journal of botany 48(3-4): 225-230. <Go to ISI>://WOS:000286892100010
  • Heenan P, Mitchell A, de Lange PJ 2010. Late-Cenozoic origin and diversification of Chatham Islands endemic plant species revealed by analyses of DNA sequence data. New Zealand journal of botany 48(2): 83-136.
  • Mandakova T, Heenan PB, Lysak MA 2010. Island species radiation and karyotypic stasis in Pachycladon allopolyploids. BMC evolutionary biology 10: 367. <Go to ISI>://000287575200001
  • Smissen RD, Heenan PB 2010. A taxonomic appraisal of the Chatham Islands flax (Phormium tenax) using morphological and DNA fingerprint data. Australian systematic botany 23(5): 371-380.
  • Voelckel C, Heenan P, Lockhart P 2010. Using studies of gene expression to investigate species radiations in the New Zealand alpine flora. Proceedings: VI Southern Connection Congress : Gondwana reunited : a southern perspective for a changing world, Bariloche, Argentina, 15-19 February, 2010.
  • Voelckel C, Mirzaei M, Reichelt M, Luo Z, Pascovici D, Heenan PB, Schmidt S, Janssen B, Haynes PA, Lockhart PJ 2010. Transcript and protein profiling identify candidate gene sets of potential adaptive significance in New Zealand Pachycladon. BMC evolutionary biology 10: 151-165.
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