Te Papa Botany researchers Heidi Meudt, Jessie Prebble and Carlos Lehnebach have recently published a new paper in the scientific journal Plant Systematics and Evolution on New Zealand forget-me-nots (genus Myosotis).

There are approximately 100 species of forget-me-not species in the genus Myosotis, about half of which are only found in New Zealand.

In the paper, we confirmed or discovered answers to the following questions about forget-me-nots:

1. What is the age of the genus Myosotis?

• Using molecular dating methods and DNA sequence data, we found that Myosotis is of Miocene age, having arisen approximately 8-20 million years ago.

2. When did the first forget-me-not arrive in New Zealand?

• We confirmed that the ancestor of today’s species of Southern Hemisphere forget-me-nots first colonised New Zealand during the Pleistocene, that is, within the last 4 million years.
• This ancestor likely came from the Northern Hemisphere. One question we unfortunately can’t answer is how it may have made that journey!

3. What are the closest relatives of New Zealand forget-me-nots?

• Species from other areas of the Southern Hemisphere including Chile (M. albiflora), Australia (M. australis, M. exarrhena), and Papua New Guinea (M. australis) are very closely related to New Zealand Myosotis.
• Chatham Island forget-me-nots (Myosotidium hortensia) are not closely related to New Zealand Myosotis.

4. How genetically diverse are the New Zealand forget-me-nots?

• Based on the DNA sequencing and fingerprinting we did, it seems that New Zealand Myosotis species have little genetic variation. This means we unfortunately have very few clues regarding the relationships among the species. Other kinds of molecular data that are more informative are needed and are under development.

This new paper is the result of several years of lab and field work at Te Papa on Myosotis, and builds upon other papers from the last few years.

One current challenge is that we do not know exactly how many endemic species we have in our flora, nor how to distinguish them from one another. Addressing this challenge is a big part of my programme of research as Research Scientist at Te Papa, so stay tuned for more blog updates in the future!