This project is the Spiral Scarf from Knitting Nature, by Norah Gaughan. Although I've only made a few of the projects in this book its one of my favorites. The photos are beautiful, and Norah's creative garment construction is so inspirational to me. And I love spotting and photographing patterns in nature myself.
The yarn is Noro Silk Garden (or maybe silk garden light?). I had originally begun making the Astrid Wrap, also by Norah Gaughan, but as I started assembling the motifs, I wasn't in love. It just wasn't the right yarn for the pattern, I loved how each motif had several colors on it, but when put together I think all the colors were just overwhelming for a larger item, and they obscured the delicacy of the shawl. But for the spiral shawl, I think the colors emphasize the scarf's unique structure. And its smaller, so avoids looking like a box of crayolas threw up.