I've got two 11" x 14" shadow boxes that I've wanted to use for paintings so I chose to use morel mushrooms for my subject, at least in one of the boxes. I'm taking a similar approach to a painting I created back in 2011. I've coated a piece of matboard with Liquitex gesso and added bits of leaves and twigs to replicate a forest floor. I also coated some oak leaves I saved from last Fall. Oak leaves are the best leaves I've found for this application because they are sturdy and pliable, even when dried. I will attach those with gel medium. I also tried out a new medium...string gel. I used it to form the mushrooms and give them a 3D appearance. The string gel was surprisingly easy to work with and I can imagine all sorts of projects I could use it for.
I found myself with lots of scrap Yupo and I hate wasting art materials so I made about a dozen bookmarks with the bits and pieces. I think they turned out rather well!