Figure 3.

A graphical cladogram representation of the tree (((a, b), c), (d, e)). In the tree, x is root, a, b, c, d and e are terminals (leaves), and y and z are internals. To determine whether a, b and c are monophyletic, the following steps are performed: I. The paths from x to a, b, and c are (x → y → z → a), (x → y → z → b), and (x → y → c) respectively. II. The longest shared segment among the three paths is (x → y). III. The LCA of a, b, and c is y. IV. The subtree rooted by y contains only a, b, and c. V. a, b, and c are monophyletic in the clade rooted by y.