On 17/01/2015 17:19, David Hill wrote:
On 17/01/2015 16:58, Spider wrote:
Something that has always puzzled me is the way the very double-flowered
dandelion attracts bees and seems to be so good for them. With most
other double flowers, bees gain very little because the many tiny
florets which make up the 'cushion' at the centre of the flower have
been turned to petals by (mostly) breeders or freaks of nature.

Does anyone here with a better grasp of botany have an explanation for
this apparent anomoly?

What I can never understand is why don't we ever see a white dandilion
or a variegated form.
You'd think that with the hundreds of millions of them growing around
the world by now we would have some different forms.
David

There are plenty of different forms - 232 (micro)species in the UK alone.

There is a white dandelion. It's called Taraxacum albidum and it grows
in eastern Asia. There is a second white dandelion. It's called
Taraxacum coreanum.

There is a pink dandelion. It's called Taraxacum porphyranthum.

But, yes, Cichorieae is strikingly conservative in flower colour, with
nearly all species having dandelion yellow flowers. Other exceptions
include pink (Crepis rubra, Crepis incana), orange (Pilosella
aurantiaca), purple (Tragopogon porrifolius), blue (Cichorium intybus,
Cicerbita sp., Catananche caerulea, Lactuca biennis, Lactuca perennis,
Lactuca tatarica) and pale yellow (some Sonchus oleraceus).

Taraxacum maculatum probably counts as a variegated dandelion.

More research finds a dandelion with pink and yellow flowers (Taraxacum
pseudoroseum), one with yellow-green variegation on the leaves
(Taraxacum 'White Flash') (and other evidence of variegated sports), and
one with purple foliage (Taraxacum "rubrifolium").

--
SRH