centerpiece fail

I have the basic concept for this centerpiece idea in my head, but I'm just not sure how to make it look right. I don't think I like the ubiquitous "votive around the flower" look that supposedly makes everything look better, so that option is out. Any suggestions?

The subtle theme of this centerpiece is chemistry. My fiance's notable traits include CHEMISTRY NERD and when I saw these lab inspired vases on CB2, I felt like I needed to incorporate them. I'm substituting a measuring cup for some kind of low beaker right now (but I'm not opposed to using carnations as I have in this picture) and fake daisies for what will maybe be bright yellow gerberas.



Something about it just doesn't look right (other than the fact that it is on a chair at the moment...)

Edit: This is mainly so I'll remember this, but these are the suggestions I've received for making this look better:
-black + white river rocks in the bottom of the vases
-taller flowers -- calla lillies or reeds?
-short centerpieces on same table, tall on others
-Something that would break it up is putting all of the tall vases on the same table but using vases of varying height. Just three vases 2" apart would achieve this. If not then just cut the long stems at 2" intervals and put 3 vases together