I have always been intrigued by the vegetation generators, and so I finally decided to give it a try. So this flavor uses:
- Strands to grow the branches: a state machine drives the branching and the level of nesting.
- Billboards particles for the leaves: leaves are 2d images with an alpha cutout projected on Quads. The Quads sizes and Orientations change based on the age of the particles.
I have also done a tutorial in PDF that you can look at if you want to know more: ICE Vine Tutorial. It contains a detailed explanation with ICE tree screen captures. Hopefully that can get you going or spawn your own ideas!