The only blue flowers we have are dyed.
We do not know of any “true blue” plant pigments. There are violets and many colors that might look close..
We do not know of any “true blue” plant pigments. There are violets and many colors that might look close..
You're referring to pigment; there is no blue plant pigment, true, but that seems a little pedantic, even if it's interesting. Plenty of flowers reflect blue light, which is what people mean when they say an object is "blue".
https://en.wikipedia.org/wiki/Blue#Pigments_and_dyes
Interestingly, the one dye listed in the link above that came from a plant is indigo, which is extracted from the green leaves of the plant https://en.wikipedia.org/wiki/Indigofera_tinctoria . There's no animal or plant I know of that both appears blue and could be used to create even a poor blue pigment, though I'd definitely be interested in any exceptions I haven't heard of.
* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5444072/
* https://www.jstage.jst.go.jp/article/fishsci1994/61/6/61_6_9... -- see figure 2 on page 4, showing extracted carotenoproteins
We have a way to describe objects which “generate a blue color when light shines on them”. We say they are “blue” objects.
Likewise, bird feathers or butterfly wings which absorb/reflect light based on their small-scale structure and appear blue are still called “blue”, even though they might be colorless when pulverized.
There are plenty of “blue flowers” out there.
> For plants, blue is achieved by mixing naturally occurring pigments, very much as an artist would mix colours. The most commonly used are the red pigments, called anthocyanins, and whose appearance can be changed by varying acidity.
It's just saying the same thing, "a red pigment appearing blue", without any explanation. (Also, as artists know, blue and red are primary colors, you can't get blue by mixing red paints.)
Microstructure interference can create blue, but perhaps not the flower pigments themselves