If you’re one of the researchers at Worcester Polytechnic Institute, University of Wisconsin-Madison, or Arkansas State University-Jonesboro, you used a leaf to grow some heart tissue.

Willows (Salix ssp) can be identified by their long, narrow leaves, which have small toothed leaf margins ... often forming a heart shape. In the fall, they turn a variety of brilliant colors ...

Further, our study characterizes, mathematically, the range of parameters that quantify the shape and diversity in leaf morphology," adds Mahadevan. The resulting model has application in ...