Tuesday, 9 October 2012

Wednesday wildflower: forget-me-not.

Garden forget-me-not, Myosotis sylvatica, Karori.

We have about half a dozen introduced species of Myosotis in New Zealand.  This one, M. sylvatica, is a common garden ornamental, and has probably escaped into the wild many times from gardens.  Although the flowers are blue, white or pink mutants arise occasionally and these have been selected and propagated by growers.  Sometimes they escape into the wild too.  It’s a bit of a clue as to how the native species came to be mostly white-flowered.
Blue and white forget-me-not flowers from separate wild plants in Glenmore St, Wellington, perhaps escapes from the nearby Botanic Gardens, where they are grown as bedding annuals.
The English name for Myosotis is forget-me-not, although the scientific name translates as mouse-ear, a reference to the shape and furriness of the leaves.  
Myosotis sylvatica leaf
Like Veronica, this genus has two main centres of diversity: Eurasia and New Zealand.  And just as in Veronica, not only do we have a large number of species, but they are very diverse in their growth forms, flower colours, flower biology, and habitats, yet show very little variation in the DNA sequences that have been studied so far.  In both genera, we probably have more variability of form in the New Zealand species than in the rest of the genus put together, but only a small proportion of the genetic variability.  That’s in keeping with the idea that these groups have arrived here quite recently (in geological terms), and that they found a lot of unfilled niches here.  Natural selection took over and populations became adapted to different habitats and pollinators so rapidly that it’s difficult to accurately trace their evolutionary history from the DNA record.  The botanists at Te Papa are studying Myosotis, and their research will document its biodiversity, aiding conservation efforts.
Myosotis capitata, SW Cape, Auckland Island.
Only two native forget-me-nots have blue flowers; the rest are mostly white with some yellow.  Both our blue forget-me-nots grow in the subantarctic islands—Auckland Islands and Campbell Island—where plants in other groups also have striking coloured flowers.  It’s easy to understand why native Myosotis and Veronica don’t generally have blue flowers in New Zealand: we have no native long-tongued social bees that are the specialist pollinators of many blue flowers in Europe.  So any chance mutants with white flowers probably reproduced better here that they would in Europe, and perhaps better than their blue-flowered relatives.  But it’s much harder to explain the presence of coloured flowers in the subantarctic, where not only are there no long-tongued social bees, but very few other flying insects.
Myosotis antarctica, Col-Lyall Saddle, Campbell Island, with Epilobium.
M. antarctica (above) is part of the rather diverse M. pygmea complex, recently split into several species and all these have very small flowers.  Some others are below:
Myosotis drucei, Black Birch Range, Marlborough, with Stellaria gracilenta.

A plant in the M. pygmaea complex, Mt Herbert, Banks Peninsula.

A plant in the M. pygmea complex, Southland coast at Waituna Lagoon.

My final native forget-me-not is M. saxosa, below.
Myosotis saxosa, Maungaharuru Range, Hawkes Bay.


  1. Hi Phil, what is known of pollination in sub-antarctic in comparison to other NZ Myosotis? Seems like an interesting question but in a very brief scan I haven't come across anything. Any suggestions where to look?

  2. Jarrod: I don't know of any research results on the subantarctic species. There is some work on inbreeding vs outcrossing among mainland species although I'm not sure how much is published.

  3. I've always wanted to go to the subantarctics. All I need now is some money.

  4. Jarrod: Google "Enderby Trust Scholarships"—you might be eligible if <35.