Does anyone know why Nasturtium flowers have those strange horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that? Please *do* let me know ;-)
--
__________
|im |yler http://timtyler.org/ Remove lock to reply.

In article , Tim Tyler writes
Does anyone know why Nasturtium flowers have those strange horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that? Please *do* let me know ;-)

Usually because the nectar is buried at the end of it to make sure the
pollinator has to go in a long way for it and gets well and truly
covered with pollen. Not sure if this is the case with nasturtiums -
haven't dissected one to see.
--
Kay
"Do not insult the crocodile until you have crossed the river"

Kay wrote or quoted:
In article , Tim Tyler writes

Does anyone know why Nasturtium flowers have those strange horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that? Please *do* let me know ;-)

Usually because the nectar is buried at the end of it to make sure the
pollinator has to go in a long way for it and gets well and truly
covered with pollen. Not sure if this is the case with nasturtiums -
haven't dissected one to see.

I believe this is not the right answer - since the "horn" contains no
flower stamens - and no pollen. The nasturtium's pollen is clearly
evident elsewhere. The horn appears to be a simple hollow tube.
--
__________
|im |yler http://timtyler.org/ Remove lock to reply.

In article , Tim Tyler writes
Kay wrote or quoted:
In article , Tim Tyler writes

Does anyone know why Nasturtium flowers have those strange horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that? Please *do* let me know ;-)

Usually because the nectar is buried at the end of it to make sure the
pollinator has to go in a long way for it and gets well and truly
covered with pollen. Not sure if this is the case with nasturtiums -
haven't dissected one to see.

I believe this is not the right answer - since the "horn" contains no
flower stamens - and no pollen. The nasturtium's pollen is clearly
evident elsewhere.

I didn't say the pollen was in the spur! I wondered if the nectar was,
so that whatever pollinates the nasturtium in its natural habitat has to
get its body well into the flower and well coated with pollen. For that
to work, you would expect the pollen to be much nearer the entrance of
the flower, which is where it is.

The horn appears to be a simple hollow tube.

Heywood (ed) Flowering Plants of the World - Tropaeolaceae (Nasturtiums
and canary Creeper) "The perianth consists of a calyx with five distinct
sepals, one of them modified to form a long nectar-spur"

However, Proctor and Yeo "The Pollination of Flowers" seems to suggest
that bees take only pollen from nasturtiums, hence my wondering what it
is pollinates nasturtiums in their natural environment. A close
relative, Tropaeolum pentaphyllum, with a similar spur, is bird
pollinated, and that makes a lot more sense with the colour - birds are
attracted more to the bright colours, hence the bright reds and oranges
that we associate with tropical flowers.

You can see how it would work - humming bird feeds its long beak down
the spur to get at the nectar, in doing so getting its feathery body
liberally coated with pollen, which is rubbed off onto the next flower
it meets.

From the plants point of view, the adaptation means only humming birds
can get the nectar, so they are the most likely visitors, and since they
get this 'reward' from the plant, they have an added incentive to visit
- so the plant gets itself pollinated by something which isn't visiting
loads of different plants with incompatible pollen.


--
Kay
"Do not insult the crocodile until you have crossed the river"

Kay wrote or quoted:
In article , Tim Tyler writes
Kay wrote or quoted:
In article , Tim Tyler writes

Does anyone know why Nasturtium flowers have those strange horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that? Please *do* let me know ;-)

Usually because the nectar is buried at the end of it to make sure the
pollinator has to go in a long way for it and gets well and truly
covered with pollen. Not sure if this is the case with nasturtiums -
haven't dissected one to see.

I believe this is not the right answer - since the "horn" contains no
flower stamens - and no pollen. The nasturtium's pollen is clearly
evident elsewhere.

I didn't say the pollen was in the spur! I wondered if the nectar was

[...]

However, Proctor and Yeo "The Pollination of Flowers" seems to suggest
that bees take only pollen from nasturtiums, hence my wondering what it
is pollinates nasturtiums in their natural environment. A close
relative, Tropaeolum pentaphyllum, with a similar spur, is bird
pollinated [...]

You can see how it would work - humming bird feeds its long beak down
the spur to get at the nectar, in doing so getting its feathery body
liberally coated with pollen, which is rubbed off onto the next flower
it meets.

Good detective work after all it seems ;-)

Nasturtiums are indeed naturally pollinated by humming birds:

``Many flowers typically pollinated by hummingbirds, such as nasturtiums,
don't need to be fragrant because their pollination partners have little
sense of smell.''

- http://www.kidsgardening.com/themes/pollinator2.asp

Now the humming bird has been mentioned, the spur's "function"
now seems clear enough - thanks!
--
__________
|im |yler http://timtyler.org/ Remove lock to reply.

In article , Tim Tyler writes

Nasturtiums are indeed naturally pollinated by humming birds:

``Many flowers typically pollinated by hummingbirds, such as nasturtiums,
don't need to be fragrant because their pollination partners have little
sense of smell.''

- http://www.kidsgardening.com/themes/pollinator2.asp

Now the humming bird has been mentioned, the spur's "function"
now seems clear enough - thanks!

And to confirm it, I spent a few minutes this morning nipping off the
end of the spur on a few nasturtiums, squeezing out a drop of liquid and
tasting its sweetness ;-)
--
Kay
"Do not insult the crocodile until you have crossed the river"

"Janet Baraclough.." wrote in
message ...
The message
from Tim Tyler contains these words:

Does anyone know why Nasturtium flowers have those strange
horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that?

It's a peg for bees to hang their hat and jacket on?

In that case I suppose the bees hold committee meetings in
long-spurred Aquilegias.

Franz

In article , Franz Heymann
writes

In that case I suppose the bees hold committee meetings in
long-spurred Aquilegias.

Interestingly, the spur in a nasturtium is a modified sepal, whereas in
the aquilegia it is a modified petal.

(I've been looking closely at spurs in the last couple of days ;-) )
--
Kay
"Do not insult the crocodile until you have crossed the river"

On Sat, 7 Aug 2004 06:06:29 GMT, Tim Tyler wrote:

Kay wrote or quoted:
In article , Tim Tyler writes

Does anyone know why Nasturtium flowers have those strange horn-shaped
bits pointing backwards?

A pictu http://www.andysmall.com/Media/Jpegs/00006.jpg

My best guess so far: flower/bee counter-weight.

Think you know better than that? Please *do* let me know ;-)

Usually because the nectar is buried at the end of it to make sure the
pollinator has to go in a long way for it and gets well and truly
covered with pollen. Not sure if this is the case with nasturtiums -
haven't dissected one to see.

I believe this is not the right answer - since the "horn" contains no
flower stamens - and no pollen. The nasturtium's pollen is clearly
evident elsewhere. The horn appears to be a simple hollow tube.

The 'horn' holds the nectar. As children, we used to bite the very tip
off the 'horn' and suck the sweet nectar.


--
Chris

E-mail: christopher[dot]hogg[at]virgin[dot]net

On Sat, 7 Aug 2004 22:03:14 +0100, Kay
wrote:

And to confirm it, I spent a few minutes this morning nipping off the
end of the spur on a few nasturtiums, squeezing out a drop of liquid and
tasting its sweetness ;-)

Some plants, which have floral 'spurs' hold the nectar within the
walls of the spur initially and young flowers may not appear to have
free nectar. Bees, butterflies and moths probe all long spurred
flowers to find out which have nectar and as a result, effect
pollination as they brush past the anthers and receptive parts of the
flower. Some plants fool insects by going to the trouble of producing
a spur, but failing to make the effort of making nectar. Canny things
plants and not all as honest as you might think! A 2 day old
Tropaeolum flower (Nasturtium) however, will have plenty of free
nectar as Kay has found out.

"Kay" wrote in message
...
In article , Tim Tyler
writes

Nasturtiums are indeed naturally pollinated by humming birds:

``Many flowers typically pollinated by hummingbirds, such as
nasturtiums,
don't need to be fragrant because their pollination partners have
little
sense of smell.''

- http://www.kidsgardening.com/themes/pollinator2.asp

Now the humming bird has been mentioned, the spur's "function"
now seems clear enough - thanks!

And to confirm it, I spent a few minutes this morning nipping off
the
end of the spur on a few nasturtiums, squeezing out a drop of liquid
and
tasting its sweetness ;-)

Watch it! You'll have the Plant Rights Activists after you. {:-))

Franz