The bunch of pink Asiatic lilies I got at Trader Joes had one white bud. Almost transulucent, with pink veins, it called out to the photographer in me.
I set the lily on a mirror, put an overhead difuse light above it, and rigged some reflections for highlights. Then I had a grand old time bracketing to extend the dynamic range of the image, but starting with what my camera thought was an overexposure. To get that transparent effect, you really want to bang the histogram to the right.
When it was all over, I inverted the luminance information in LAB color to get the effect below. If one lily is nice, then two are twice as much fun!
This is more or less the same technique I used recently on some Papaver (poppy) buds, treated for transparency. I like the way the poppies came out a bit better, but the glossy transparent look here is really a one-off, and has some charms of its own.
View this image larger.