> I've been trying to discover why Drosera flowers vary in nature
> here in Brazil and though I don't have any conclusions yet, I have strong
> suspicions. The species which probably varies the most is D.communis,
> having flower from pure white to lilac. Of the native Brazilian
> species, I'd say this one is the most similar to D.rotundifolia and is
> probably its closest parent down here. By what I've seen, 2 ecological
> factors are surely involved with flower color. These are sunlight
> intensity and soil humidity. When the soil is drier and the sunlight more
> intense, the flowers are lighter in color and vice versa.
My rotundifolia are quite a bit more humid in the terrarium than
out of it, and they're still in a seed tray so the relative
water level is higher - could be the critical factor I guess.
I shall sow some of this season's seed in a few different
environments and see what happens...
> I recently went
> to a D.communis site near S.Paulo city where the plants had lilac
> flowers. The funny thing is that when I went there around 2 years ago,
> all plants had light-lilac flowers, almost white. Back then it had been
> rather sunny and dry (I think) for a few weeks and this time it had been
> raining intensely over the previous few weeks. Thus it would be the
> opposite of what's happening to your D.rotundifolia flowers, which are pink
> and right up against the lights. Another factor I think influences flower
> color is pH. I'm not sure if alcaline soils promote plants to
> produce lighter-colored flowers and acidic soils make them darker or vice
> versa. I think soil pH might even be more important than humidity since
> I've found D.communis with white flowers growing in one boggy area and
> light-lilac flowered ones growing 1 or 2km away. I've noticed that some
> regions often have just one or the other color and sometimes they're
> even mixed in the same bog! It might be some other chemical in the soil,
> who knows?!
I didn't measure my ph last year, but it's good and acidic now (I've
only got litmus to hand at the moment, so 'very red'.)
Same proportions of peat and sand, but a new bag of sand since last
year.
I wonder if algae or bacterial action might play a part? - reduced
oxygen levels in the water? CO2 build-up from reduced ventilation
(hmm, can anyone remember the test for carboxylic acid? )
When it rains on the bogs perhaps it flushes out whatever has built
up, perhaps at a critical time in the flowering process...
Are the colours separated by time perhaps? - if heavy rain altered
the soil chemistry in the middle of the critical period (whenever
that might be,) then the early flowers could be different from the
late ones...
Hmm, it's a thought.
Happy growing,
Peter
Peter Cole | carnivor@bunyip.demon.co.uk |
Swansea, WALES | old mailboxes still active |