Julie J. Rehmeyer has an article in Science News about the mathematics of phylogenetic trees.
"Now, mathematicians have developed a new understanding of the mathematics of tree-shaped graphs, which makes possible the statistical analysis of evolutionary trees. The development will help biologists to make sense of the flood of newly available genetic information."Looks interesting.
"Susan Holmes, a statistician at Stanford University, and mathematicians Louis Billera and Karen Vogtmann of Cornell University in Ithaca, N.Y., have found a way to quantify the difference between two trees, effectively determining the distance between them. They used this distance function to construct a "space" of trees, a sort of theoretical forest."