Re: New Zealand Flora
Loren Russell wrote:
>
> Island biotas, like NZ, are about the first things to come to mind when I
> hear the complaint that evolution isn't "scientific", because it's telling
> stories about things that are just history, rather than doing experiments.
> In fact, each island, and its island group, is a separate experiment is
> evolution, and the results we see usually make sense, given the original
> colonists in each story.
Loren
Thanks for all your comments which help to flesh out and confirm a lot
of what I suggested.
> Evergreen habit: this is interesting too, but remember that evergreen is
> the original, primitive, trait in woody plants. The deciduous habit
> becomes usual both in cold-winter, nice summer, and in really-nasty dry
> season subtropical environments. So continental vs. oceanic climates
> correlate. But Gondwanaland WAS an ideal place for deciduousness to
> evolve. It was huge, and so predominately continental in climate, and it
> spent a lot of time in polar-to-temperate array. NZ did start with
> Gondwana elements, but to the degree that its flora is PRIMITIVELY
> evergreen, this is due to the early date of separation, not the climatic
> conditions in the southern continents.
Yes, I did intend to emphasize that the evergreen feature was a
primitive one and its NZ prevalence related to the early separation.
> Another puzzle: Why all the brown? I don't think there's any place else
> on earth where kelp-brown foliage is common. It occurs [among species
> I've seen in cultivation] in alpine hebes, sedges, grasses, Arthropodium
> [a lily], a few raoulias, corokia.... I'd guess that NZers could fill in
> others. Most of the ones I mention are alpine [because I grow alpine
> plants], so could it relate to something about the "quality of light". Or
> is it the moas again: browser/grazer types with color vision???
I think it is almost certainly a response to the light quality,
particularly to very high UV. It occurrs not only among alpines but
quite frequently in seacoast plants, which would suffer much the same
exposure. I don't think we can really bring the moas into this one!!
I can extend your list a bit with some fine-leaved creeping coprosmas,
such as C brunnea, and a natural sport of the hop bush (Dodonea viscosa)
which is normally green in the wild, but has produced a varient with
brownish leaves or even, in the best selected forms, deep purplish
crimson foliage.
In cultivation you also see brown leaved Cabbage trees (Cordyline) and
Flaxes (Phormium), but I rather think these are human-induced and not
present in wild populations.
Forgive me if I use the end of this letter to comment on an error you
certainly were not responsible for, but which was in a posting I seem to
have failed to keep. It related to our poor, most probably by now very
confused, so-called Mount Cook Lily. Someone threw out in passing that
this was a composite. Well, it is neither a lily or a daisy, but a
truely magnificent white buttercup (Ranunculus lyallii) up to a metre
tall, which is confined to the wetter mountain areas of the South
Island. Alas, while a vigorous "weed" in its prefered mountain fastness,
it languises and fades away if exiled to warmer and drier lowlands.
There is a whole series of mountain buttercups here, both golden and
white, but none as fine as this one.
Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata,
New Zealand (astride the "Ring of Fire" in the SW Pacific).
