Thursday, 14 February 2013

Elingamita johnsonii

The Three Kings Islands sit a bit north of North Cape, and they have a few peculiarities in their flora.  Two of them, Cordyline kaspar and Piper melchior, are named after two of the biblical three kings (the aliteration was lost when the genus Macropiper was combined with Piper recently).  Altogether, there are reckoned to be 13 endemic plant species on the Three Kings, very high for such a small area of land.

Two of them, Pennantia baylisiana and Tecomanthe speciosa, must be the world's equal rarest plants, because both are known from only single individuals on the Three Kings Islands.  You could argue that P. baylisiana is even rarer because the only plant is a female; however somehow it occasionally produces fruits which are a prospect for its reintroduction in the wild.  Both are well established in New Zealand gardens.
Elingamita johnsonii in my garden.
Elingamita johnsonii is another Three Kings endemic, but it's known from a few dozen plants.  It's classified in the Myrsinaceae, along with our native species of Myrsine, to which it's thought to be very closely related.

The plant in my garden is a male, and I've had it about 20 years.  For some of that time it lived in a pot in my office, where it suffered badly from scale insects.  After a while I took a risk and planted it out in the garden, and it hasn't looked back.  Now I'm having to build a dog-leg in a new retaining wall, to avoid burying its roots.

Elingamita johnsonii, male flowers starting to open
This year it's flowering heavily.  The flowers seemed to open a few weeks ago, with prominent large golden anthers, but these have sat for a long time without shedding pollen.  When I read the original description, I noted the flowers were said to have long stamen filaments, and now, after doing nothing for a few weeks, the filaments are elongating and the anthers opening to release their pollen.  The lower parts of the flower are also turning pink.  Although male, these flowers seem to have quite a well-developed ovary, style, and stigma, but I've never had fruit from this tree.
Elingamita johnsonii, male flowers.
Tītoki male flowers delay the final development and opening of their anthers in much the same way.
Elingamita johnsonii, a male flower soon after opening
Elingamita johnsonii.  At a later stage, when the filaments begin to elongate (right) and the anthers release their pollen (left).
The flowers are said to be quite different from those of Myrsine.  First the petals are joined into a short skirt-like tube; you can see it in the photo above.  Secondly, the stigma is small, with a little depression in it, punctiform.  In Myrsine, the petals don't form a skirt-like tube although they may be partly joined (see below) and the stigma is large and broader than the style.  These differences might not be very major in a genetic or developmental sense, and they probably reflect something about the pollination biology of these plants, rather than telling us much about their relationships.
Myrsine australis female flower.  Note the expanded stigma (out of focus in the centre).
Myrsine australis male flower.  Note that the four petals are shortly joined into a tube
If you're thinking about classification, here's a familiar dilemma.  E. johnsonii flowers look different from those of Myrsine, yet a Massey University PhD thesis by Karen Stöckler indicates Elingamita is very closely related to New Zealand species of Myrsine.  You'll know if you've read my previous postings on Veronica and Lobelia that I am strongly in favour of classifying plants with their nearest relatives rather than with look-alikes.  Interestingly, Pennantia baylisiana was similarly once classified in its own genus Plectomirtha.  Karen and I are collaborating on considering this question.

How did Elingamita come by its name?  It's named after the S.S. Elingamite, which ran aground in 1902 on West Island in the Three Kings, with the loss of forty-five lives.  One other native plant I know of commemorates a shipwreck: Lepidium naufragorum, a coastal cress.  The name refers to cast-aways, nine (correction 16 Feb 2013: the accounts I've linked to say ten) sealers who were dropped on the Open Bay Islands in 1810.  Their ship was never seen again, but they were rescued after 4 years of hardship.
Lepidium naufragorum.

1 comment:

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