Eileen, The Minnesota Council of Teachers of Mathematics featured Millie Johnson of Western Washington University as a keynote speaker at the 1993 Fall Conference. Her talk was a wonderful collection of fractal structures - rivers branching, artery structure, branches of plants, etc. She gave a similar talk at the NCTM meeting in Boston. I don't have an e-mail address for her but her snail mail address is:
Millie Johnson Western Washington University 935 W. Lake Samish Bellingham, WA 98226
Good luck in your explorations with your students!
Arnie Cutler K-12 Education Coordinator The Geometry Center