Taxa

• Craspedia
• Epilobium
• Myosotis
  
• Nothofagus
• Ourisia
• Pachycladon
• Pittosporum
• Plantago
  
• Ranunculus
• Tragopogon
• Veronica
• Wahlenbergia
  

Plantago

Plantago (including Bougeria and Litorella) is a world-wide genus of mostly herbaceous wind-pollinated plants. Their adaptations to wind pollination and distinctive circumscissile capsules had previously led to their taxonomic isolation in their own small family, Plantaginaceae. However recent molecular systematics research has led to recognition that a large group of plants that previously had been included in Scrophulariaceae are in fact related to Plantago (e.g., Albach et al. 2005). For example, Veronica, Antirrhinum, Digitalis, Linaria, and Ourisia all now belong in an enlarged Plantaginaceae, making it one of the largest families in the New Zealand flora. Research on New Zealand Plantago is part of a project based at Museum of New Zealand Te Papa Tongarewa to revise the family Plantaginaceae in New Zealand towards a new eFlora treatment.

The Plantago project began with the MSc research of Mei Lin Tay at Victoria University, supervised by Phil Garnock-Jones, Heidi Meudt, and Peter Ritchie. Molecular phylogenetic analyses of three markers representing three different genomes (nuclear ribosomal internal transcribed spacer region (ITS), chloroplast ndhF–rpl32, and mitochondrial coxI) showed that native New Zealand species of Plantago do not form a monophyletic group (Tay et al. 2010a). Mei Lin found that there have been at least three invasions of New Zealand by Plantagos from Australia, these occured approximately 2.3-0.5 million years ago, and each has led to a modest species radiation in New Zealand. This result differs from the biogeographic pattern often reported for New Zealand plant genera of a single dispersal event followed by rapid radiation, and may be attributed to ready biotic dispersal of mucilaginous seeds and habitat similarities of the Australasian species (Tay et al. 2010a).

By sequencing many additional individuals of New Zealand Plantago for the ITS region, Mei Lin was able to reconstruct the population-level phylogenies and networks which provided evidence for the recognition that the two P. spathulata subspecies, and a 16-ploid tag-named entity ( P. sp. "Sylvester"), should each be recognized at species rank (Tay et al. 2010b). ITS sequences were unable to distinguish between two P. raoulii forms suggested by field botanists, P. lanigera and P. novae-zelandiae, and two P. triandra subspecies. In general, Mei Lin's research (Tay et al. 2010a, b) highlighted a complex pattern of DNA sequence evolution, which combined with known chromosome numbers and morphological data, suggested a history of hybridisation and hybrid species formation, and set the stage for the additional research that followed (e.g. chromosome counts, molecular cytogenetics, morphological data, and additional DNA loci; see below).

More recently, the research has been continued by Heidi Meudt, focusing on AFLP profiling and morphometrics, and Brian Murray and his MSc student Charles Wong at Auckland University, focusing on chromosome numbers and genomic in-situ hybridisation. First, several new mitotic and meiotic chromosome counts (made from 58 individuals representing most native species and subspecies of Plantago) confirmed previous counts for many species, and highlighted a new number (2n=12x=72) for four individuals identified as P. unibracteata (Murray et al. 2010). These results provide further evidence that the base number of all native New Zealand Plantago is x=6, and most polyploids are allopolyploids. Using molecular cytogenetics, Wong & Murray (2012) found that there were large differences in C-value between New Zealand Plantago species but the extent of changes associated with different polyploid events was highly variable.

Phylogenetic and other analyses of amplified fragment length polymorphism (AFLP) DNA fingerprinting were useful for further testing of species boundaries and interpretation of polyploid origins in this taxonomically challenging group (Meudt 2011). Congruent with Tay et al. (2010a), there were three main lineages of native New Zealand Plantago, and within each of these some species were easily distinguished. Thus the largely diploid group III contained several genetically-distinct species ( P. novae-zelandiae, P. lanigera, P. obconica, and P. aucklandica), the polyploid group II showed little genetic differentiation ( P. masoniae, P. triandra, and P. unibracteata), and the polyploid group I comprised species that were clearly genetically distinct (including P. sp. “Sylvester” and P. picta) and others whose boundaries were less clear ( P. raoulii and P. spathulata).

Finally, Meudt (2012a) recognised 11 native species in a recently-published taxonomic revision. Analyses of novel morphological data were coupled with the previously published studies mentioned above. Several morphological characters (e.g., seed number, seed shape, hairiness of scapes, bracts and sepals, and number of flowers and spikes) were found to be particularly important characters for species delimitation in the group. The main differences with previous treatments include: the recognition of Plantago picta at species rank, the synonymy of Plantago masoniae with Plantago triandra, and the description of a new 16-ploid species, Plantago udicola Meudt & Garn.-Jones (previously tag-named P. sp. "Sylvester"). Meudt (2010b) provides a short, readable overview of these and other taxonomic changes.

References:

Meudt, Heidi M. 2012b. New Zealand native Plantago taxonomy revised. Trilepidia 105:4-5. Article

Wong, Charles, and Brian G. Murray. 2012. Variable changes in genome size associated with different polyploid events in Plantago (Plantaginaceae): Genome size and polyploidy in Plantago. Journal of Heredity doi: 10.1093/jhered/ess049 Article

Meudt, Heidi M. 2012a. Taxonomic revision of New Zealand endemic species of Plantago (Plantaginaceae). New Zealand Journal of Botany 50(2):101-178. Article

Meudt, Heidi M. 2011. AFLP data reveal a history of auto- and allopolyploidy in New Zealand endemic species of Plantago (Plantaginaceae): New perspectives on a taxonomically-challenging group. International Journal of Plant Sciences 172:220-237. Article

Murray, Brian, Heidi M. Meudt, Mei Lin Tay, and Phil Garnock-Jones. 2010. New chromosome numbers in New Zealand species of Plantago (Plantaginaceae). New Zealand Journal of Botany 48(3):197-204. Article

Tay, Mei Lin, Heidi M. Meudt, Phil Garnock-Jones, and Peter Ritchie. 2010b. Testing species limits of New Zealand Plantago (Plantaginaceae) using internal transcribed spacer (ITS) DNA sequences. New Zealand Journal of Botany 48(3):205-224. Article

Mei Lin Tay, Heidi M. Meudt, Philip J. Garnock-Jones, Peter A. Ritchie 2010a. DNA sequences from three genomes reveal multiple long-distance dispersals and non-monophyly of sections in Australasian Plantago (Plantaginaceae). Australian Systematic Botany 23: 47–68. Article

Albach, Dirk C., Heidi M. Meudt, and Bengt Oxelman. 2005. Piecing together the “new” Plantaginaceae. American Journal of Botany 92: 297-315. Article