Research on Myosotis

People: Heidi Meudt, Jessie Prebble, and Carlos Lehnebach

The main aim of Te Papa's research on native New Zealand species of forget-me-nots (Myosotis, Boraginaceae) is to produce a taxonomic revision of all native New Zealand species of the genus, as well as a new eFlora treatment (www.nzflora.info). Myosotis species display an amazing amount of diversity regarding habit, flower shape and colour, and ecology.

There are about 90 species of forget-me-nots native to temperate areas of both the Northern and Southern Hemispheres. Myosotis plants display an amazing amount of diversity regarding habit, flower shape and colour, and ecology. Currently, there are 44 described species, subspecies and varieties of native New Zealand forget-me-nots. Several other forget-me-nots have been given informal tag-names, suggesting New Zealand may harbour even more species. As a high proportion-about 85%-of the New Zealand forget-me-nots are considered to be Threatened, Naturally Uncommon - At Risk, or Data Deficient, Myosotis is a top conservation priority.

There is an urgent need for further systematic research on New Zealand forget-me-nots. The latest taxonomic revision is 60 years old and does not take into account additional studies on chromosome numbers, ecology, pollination biology, and preliminary phylogeny that have been published over the last 15 years.

Our current research on New Zealand Myosotis will build upon these previous studies to address the following questions:

• How are the New Zealand forget-me-nots related to one another and to their overseas relatives?

• How many New Zealand species are there, how can they be identified, where are they found, and what is their conservation status?

• Why are there so many rare, threatened species of Myosotis in New Zealand?

To do this, we perform field work to collect and photograph specimens, which then become part of the collection at the Te Papa herbarium. We use these and other specimens in performing analyses of DNA sequences, DNA fingerprinting and genotyping, morphological characters, and other data to elucidate the phylogeny, delimit species, and revise the taxonomy of the group. We publish our research results in the scientific literature and highlight our findings on the Te Papa blog and in popular publications.

Our focus is currently on the following species groups: M. forsteri and M. venosa (Carlos Lehnebach) and several species groups of ebracteate, erect forget-me-nots (Heidi Meudt). Jessie Prebble (a former PhD student based at Te Papa and Massey University, now at Manaaki Whenua - Landcare Research) is finalising the taxonomy treatment of the pygmy forget-me-nots.

Since starting research on New Zealand forget-me-nots in 2010, Te Papa scientists have:

• Revised five species subgroups in the ebracteate-erect group of Myosotis, including describing two new subspecies;

• Tested species boundaries using morphology and pollen in the Myosotis australis group, including species from Australia and New Guinea;

• Tested species boundaries using morphology and genotyping in the pygmy forget-me-nots;

• Revised the bracteate-prostrate group of Myosotis, including describing three new species;

• Analysed pollen to determine which pollen characters are useful for distinguishing species and species groups in the bracteate-prostrate Myosotis group;

• Developed microsatellite markers for the Myosotis pygmaea species group, which also amplify across species;

• Performed DNA sequence and molecular dating analyses to determine the main lineages, relationships and age of Southern Hemisphere Myosotis , as well as test an informal classification;

• Analysed morphological and molecular data to revise the Myosotis petiolata complex, raising two varieties to the species level and describing a new subspecies;

• Described two new species of Myosotis native to the South Island of New Zealand; and

• Clarified the types of M. goyenii, M. forsteri, M. australis.

Te Papa's research on Myosotis is funded by Core funding for Crown Research Institutes from the Ministry of Business, Innovation and Employment’s Science and Innovation Group.

References

HM. Meudt. 2021. Taxonomic revision of five species groups of ebracteate-erect Myosotis (Boraginaceae) endemic to New Zealand based on morphology, and description of new subspecies. 2021. Australian Systematic Botany. 34, 252-304. 

HM Meudt, Thorsen MJ, Prebble JM. 2020. Taxonomic revision of the Myosotis australis group (Boraginaceae) in Australia, New Zealand and New Guinea. Australian Systematic Botany 33(6):477-524. 

Prebble JM, Symonds VV, Meudt HM, Tate JA. 2019. How many pygmy forget-me-not species are there? Testing the morphology-based taxonomy of the New Zealand native Myosotis pygmaea species group with population genetic data. Taxon 68(4): 731-750.

Prebble JM, Meudt HM, Tate JA, Symonds VV. 2018. Bolstering species delimitation in difficult species complexes by analysing herbarium and common garden morphological data: a case study using the New Zealand native Myosotis pygmaea species group (Boraginaceae). Systematic Botany 43(1): 266-289. 

Meudt HM, Prebble JM. 2018. Species limits and taxonomic revision of the bracteate-prostrate group of Southern Hemisphere forget-me-nots (Myosotis, Boraginaceae) including description of three new species endemic to New Zealand. Australian Systematic Botany 31(1): 48-105.

Meudt HM. 2016. Pollen morphology and its taxonomic utility in the Southern Hemisphere bracteate-prostrate forget-me-nots (Myosotis, Boraginaceae). New Zealand Journal of Botany 54:475-497.

Prebble JM, Tate JA, Meudt HM, Symonds VV. 2015. Microsatellite markers for the New Zealand endemic Myosotis pygmaea species group (Boraginaceae) amplify across species. Applications in Plant Sciences 3(6): 1500027.

Meudt HM, Prebble JM, Lehnebach CA. 2015. Native New Zealand forget-me-nots (Myosotis, Boraginaceae) comprise a Pleistocene species radiation with very low genetic divergence. Plant Systematics and Evolution 301: 1455-1471.

Meudt HM, Prebble JM, Stanley RJ, Thorsen MJ. 2013. Morphological and amplified fragment length polymorphism (AFLP) data show that New Zealand endemic Myosotis petiolata (Boraginaceae) comprises three rare and threatened species. Australian Systematic Botany 26: 210-232.

Lehnebach CA. 2012. Two new species of forget-me-nots (Myosotis, Boraginaceae) from New Zealand. Phytokeys 16: 53-64.

Lehnebach CA. 2012. Lectotypification of three species of forget-me-nots (Myosotis: Boraginaceae) from Australasia. Tuhinga 23: 17-28.