Journal Article

Biosystematics and Conservation: A Case Study with Two Enigmatic and Uncommon Species of <i>Crassula</i> from New Zealand

P. J. De Lange, P. B. Heenan, D. J. Keeling, B. G. Murray, R. Smissen and W. R. Sykes

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 101, issue 6, pages 881-899
Published in print April 2008 | ISSN: 0305-7364
Published online November 2007 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcm294
Biosystematics and Conservation: A Case Study with Two Enigmatic and Uncommon Species of Crassula from New Zealand

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  • Ecology and Conservation
  • Evolutionary Biology
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Background and Aims Crassula hunua

and C. ruamahanga have been taxonomically controversial. Here their distinctiveness is assessed so that their taxonomic and conservation status can be clarified.

Methods

Populations of these two species were analysed using morphological, chromosomal and DNA sequence data.

Key Results

It proved impossible to differentiate between these two species using 12 key morphological characters. Populations were found to be chromosomally variable with 11 different chromosome numbers ranging from 2n = 42 to 2n = 100. Meiotic behaviour and levels of pollen stainability were both variable. Phylogenetic analyses showed that differences exist in both nuclear and plastid DNA sequences between individual plants, sometimes from the same population.

Conclusions

The results suggest that these plants are a species complex that has evolved through interspecific hybridization and polyploidy. Their high levels of chromosomal and DNA sequence variation present a problem for their conservation.

Keywords: Chromosome variation; Crassula; Crassula hunua; Crassula ruamahanga; Crassulaceae, conservation; phylogenetics; taxonomy; New Zealand flora

Journal Article.  10984 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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