Meet the wonderfully spectacular Motu Maha Auckland Islands endemic species, Plantago aucklandica. Botany Curator Heidi Meudt explains why this plant was such a thrill to see in the field on the Strannik 2023 Auckland Island Expedition, how it differs from the other ten species of native New Zealand plantains, and why she thinks it deserves to be called a megaherb.
Introducing Plantago aucklandica
Plantago aucklandica was first collected and described by Joseph Dalton Hooker in 1840 on the Ross Expedition. Since then, it has been collected on a few other expeditions, and is only known from Motu Maha Auckland Islands on Auckland Island and Adams Island.
Plants of this species are only found above the bushline in Motu Maha Auckland Islands, habitats which are not generally easily accessible to tourists or researchers. Therefore, very little is known about its distribution, ecology and populations sizes on the island – so we weren’t sure what to expect on our recent Strannik 2023 Auckland Island Expedition.
What we found on Auckland Island really blew us away: from about 350 m elevation and above, there were thousands upon thousands of Plantago aucklandica plants! As expedition co-leader Alex Fergus mentioned in a previous blog, we were just as awestruck as Joseph Dalton Hooker was, and we felt immense joy at meeting these massive plantains for the first time.
We made the first (and so far only) observations on iNaturalist on our expedition, and we also collected seed and specimens for Te Papa at three different locations.
Seeing Plantago aucklandica in its natural habitat was a dream come true. The sheer number of P. aucklandica plants that we saw made us giddy with excitement, and we were also relieved to know that these endemic plants are secure. In spite of the pigs on Auckland Island, the species is currently thriving in its native habitat.
Plantago aucklandica does not appear to be particularly palatable and therefore the effect of pigs is damage to its habitat rather than the targeting of plants. Also, the damp, peaty, acidic soils that it grows in are less targeted by pigs than some other soils and ecosystems on the island.
Plantago triantha is also native to Motu Maha Auckland Islands
But Plantago aucklandica is not the only native species of plantain on Motu Maha Auckland Islands! Plantago triantha is also found there, in coastal areas rather than alpine habitats (and it’s also native to Tasmania, Australia).
Plantago triantha is similar in appearance and habitat preferences to the similarly-named Plantago triandra found on mainland New Zealand.
We found several populations of Plantago triantha on our expedition too, making iNaturalist observations and collecting Te Papa specimens.
Here’s a fun fact – I’m now possibly one of the few people in the world who has seen and collected every native New Zealand species of Plantago. (If you think you might also be in this exclusive club, please let me know in the comments!)
What makes Plantago aucklandica unique?
Like many other plantains, plants of Plantago aucklandica are rosette herbs with leaves that have parallel veins, and flowers that are small, drab, inconspicuous, wind-pollinated, and clustered together into inflorescences called spikes.
Its fruits are tiny dry capsules, which split open around the middle to reveal the cup-shaped capsule base and the even tinier seeds inside.
New Zealand plantains can show a lot of variation in leaf characteristics, for example regarding size and shape, number and size of teeth on the leaf edges, number of veins, and how hairy they are. For example, Plantago udicola and P. raoulii can also have large leaves like Plantago aucklandica.
So leaf characteristics are not as useful for identifying the species as other traits. The best features for telling the New Zealand plantains apart from one another are the flowers, scapes (the stalk supporting the spike), capsules, and seeds. Some of these traits can be quite small and are best seen with a magnifying glass or microscope.
Plantago aucklandica differs from all of the other New Zealand in that it has fewer, larger leaves with wide petioles, and many parallel leaf veins – up to seven per leaf.
It has long and narrow spikes with as many as 130 flowers, way more than the other species.
The tiny flowers have only two ovules in the ovary, but usually only one of these develops, so that the dry capsule fruit only has one seed in it, which is a unique characteristic amongst New Zealand Plantago.
All other New Zealand plantains have at least two seeds, and up to 42 seeds per capsule. The seeds of Plantago aucklandica are also unique in that they have a bumpy surface (colliculate) rather than a netlike surface (reticulate).
In our published research into the taxonomy, relationships, and biogeography of New Zealand Plantago, we found that Plantago aucklandica is closely related to the other New Zealand species (especially Plantago lanigera and Plantago obconcia, among others) as well as some from Australia.
Interestingly it also is related to two other island endemics: Plantago hedleyi from Lord Howe Island – which was photographed by Te Papa scientists Leon Perrie and Lara Shepherd on a 2023 field trip there – and Plantago stauntonii from Île Amsterdam in the Indian Ocean.
Plantago aucklandica is a megaherb!
Plantago aucklandica is a very large plantain compared to its New Zealand and Australian relatives, and displays several of the characteristics that define subantarctic megaherbs that I discussed in my previous blog (Nicolls & Rapson 1999).
Large, leathery (sometimes hairy!), deeply veined leaves in a rosette? Tick.
A fleshy root system? Tick.
Rigid but not woody plant tissue? Tick.
Colourful flowers? Well, no. But not all the other megaherbs have this characteristic either (e.g. Azorella polaris has yellowish flowers).
Plantago aucklandica is a large, unique, large-leaved subantarctic plant whose unusual form and characteristics fit the subantarcitc megaherb profile.
It is a unique plant that is only found in high-elevation habitats on Motu Maha Auckland Islands, forming a dominant part of the alpine flora. Including it among the ranks of the iconc megaherbs will allow more people to know, understand, appreciate, and indeed celebrate the immensely wonderful and beautiful plant that is Plantago aucklandica.
Acknowledgements
Special thanks to fellow Strannik 2023 Auckland Island Expedition botanists Alex Fergus and Brian Rance for their comments and contributions to this blog post.
Further reading
- Hassemer, G., Bruun-Lund, S., Shipunov, A. B., Briggs, B. G., Meudt, H. M., & Rønsted, N. (2019). The application of high-throughput sequencing for taxonomy: the case of Plantago subg. Plantago (Plantaginaceae). Molecular Phylogenetics and Evolution, 138, 156-173. https://www.sciencedirect.com/science/article/pii/S1055790318307206
- Iwanycki Ahlstrand, N., Verstraete, B., Hassemer, G., Dunbar‐Co, S., Hoggard, R., Meudt, H. M., & Rønsted, N. (2019). Ancestral range reconstruction of remote oceanic island species of Plantago (Plantaginaceae) reveals differing scales and modes of dispersal. Journal of Biogeography, 46(4), 706-722. https://onlinelibrary.wiley.com/doi/full/10.1111/jbi.13525
- Meudt, H. M. (2011). Amplified fragment length polymorphism 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(2), 220-237. https://www.journals.uchicago.edu/doi/abs/10.1086/657657
- Meudt, H. M. (2012). A taxonomic revision of native New Zealand Plantago (Plantaginaceae). New Zealand Journal of Botany, 50(2), 101-178. https://www.tandfonline.com/doi/full/10.1080/0028825X.2012.671179
- Nicholls, V. J., & Rapson, G. L. (1999). Biomass allocation in subantarctic island megaherbs, Pleurophyllum speciosum (Asteraceae) and Anisotome latifolia (Apiaceae). New Zealand Journal of Ecology, 87-93. https://newzealandecology.org/system/files/articles/NZJEcol23_1_87.pdf
- Plantago aucklandica. Wikipedia article. https://en.wikipedia.org/wiki/Plantago_aucklandica. Accessed 5 Nov 2023.
- Ross, James Clark. 1847. A voyage of discovery and research in the southern and Antarctic regions, during the years 1839-43. https://doi.org/10.5962/bhl.title.98449
- Tay, Mei Lin. 2008. Evolution of Australasian Plantago (Plantaginaceae). MSc thesis. Victoria University of Wellington. https://researcharchive.vuw.ac.nz/xmlui/bitstream/handle/10063/357/thesis.pdf?sequence=1
- Tay Mei Lin, Meudt Heidi M., Garnock-Jones Philip J., Ritchie Peter A. (2010) 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. https://www.publish.csiro.au/SB/pdf/SB09040
- Tay, M. L., Meudt, H. M., Garnock-Jones, P. J., & Ritchie, P. A. (2010). Testing species limits of New Zealand Plantago (Plantaginaceae) using internal transcribed spacer (ITS) DNA sequences. New Zealand Journal of Botany, 48(3-4), 205-224. https://www.tandfonline.com/doi/pdf/10.1080/0028825X.2010.518318
- Webb, C. J., & Simpson, M. J. (2001). Seeds of New Zealand gymnosperms and dicotyledons. Manuka Press.
Other blogs in this series
- The megaherbs of Motu Maha Auckland Islands
- The 2023 Strannik Auckland Island Expedition: Our favourite places and plants
- Flora of Motu Maha Auckland Islands
- The 2023 Strannik Auckland Island Expedition: An extraordinary botanical voyage to the subantarctic
