An Idea Confirmed!

You know, for the last few years, using a not-very-high-powered binocular microscope, I’ve had this idea that there must be, on the upper surface of a rose petal, a layer of lens-like cells. When these where fully hydrated, they gave rose petals their sparkle. When they became dehydrated, these, I thought from what I was seeing, give some roses their black or dark grey/violet “velvet” areas (which would be why some roses get darker with age, like Ruby Meillandecor does in my garden, or Veilchenblau). That’s why I’ve been searching for a good diagram of a slice through a petal…

Yahoo! There are indeed such cells, and they function, at least in part, as I thought! The article below doesn’t mention roses particularly, but it’s nice to know one is on the right track!

Link: news.bbc.co.uk/1/hi/sci/tech/8049954.stm

I do not know about roses but in hermocallis (daylilies) there is several layer of cells that make up what we would call the flower color. the top layer is clear. Many daylilies have what is called gold dusting or silver dusting which is in the second layer of cells which make them sparkle like they had glitter sprinkled on them. This pigment is however impossible to photo graph so you have to rely on descriptions in order to find plants with it. The next time you see a ‘stella de ora’ take a look at the petals up close you will see this gold dusting. For those who do not know which one is stella it is a miniature golden yellow commonly found in almost all new parking lot developments in the US. I have been keeping an eye out for this sort of thing in roses but so far I have not seen it on any.

But even if I do not find the gold dusting it is important to note that rose flowers just like every other flower I know of is made up of layers and it the sum total of the layer that make up what it looks like. As a painter I add layers to a painting to add depth and to build up color and tints. In this way a painting does not look flat. I think flowers that look flat probably have layers made up of the same color and flowers that have depth probably have layers made up of different colors or different tints and tones of the same color.

These layers are probably one of the reasons tetraploids look so much more colorful then most diploids. Simply because the they have more layers (plus the possible pallet is bigger).

Another thing to keep in mind layers can play tricks on your eye. Not through the addition theory of color. Say red and blue make purple. But through the subtraction theory. Which I will try to explain the best way I can. First of all this color theory says their is no true primary colors but they are made up of a spectrum of colors. Say we have a pigment that is red but it is more orange red then violet red when we add this to the a pigment that is violet blue instead of a bright violet or purple we get a dull purple or a weird brown. This is because the pigments absorb each other and what we are left with are only a small amount of the purple color.

Sorry I think I got a little off topic but it is something to think about at least. If anyone knows of a rose that has even a hint of glitter in the petals tell me and I would definitely work with it in your own program. It took people like Bill Munson a good decade to really figure out this trait but once they did it really took off.

Very interesting topic. Adam, is silver or gold dusting determined by the underlining color? Have seen it referred as diamond dusting also. Love it in daylilies. Gives it that fluourescent sparkle.

I have Heidelberg, a 1959 Kordes cross of World’s Fair x Floradora. It is a tall shrub(climber) of salmon red coloration. What I have observed is when the flower first opens, it has a sparkle or glossy sheen to it which reminds me of the fluorescent jackets (ugh) popular in my high school days. This seems to last a day or so and then the rose has a plain salmon red coloration. When I first saw it it reminded me of the diamond dusting on certain daylily cultivars. It makes the flowers sparkle even at a distance. My Floradora does not show this and I had World’s Fair only for a year or two before it died yet I do not recall it having this quality either. I recall a small rose nursery saying it had Heidelberg in its front and it received so many comments they added a second. I wonder if it was this sparkle that made it stand out.

Jim

Silver and gold dusting is the same as diamond dusting. It is independent of the underlining color. It does tend to look best on yellow and white flowers however. I will have to look at Heidelberg.