Figure 2From: A scalable method for identifying frequent subtrees in sets of large phylogenetic trees(a) A rooted, bifurcating phylogenetic tree T built on five taxa labeled with a, b, c, d and e. The internal nodes are shown with x0, x1, x2 and x3. (b) A clade of T rooted at x1. (b) and (c) Two subtrees of T by contracting the taxa sets {d, e} and {a, e}.Back to article page