Tree A is in polar format (often called a circle tree). This is basically the same as the trees above but in polar coordinates. The vertical dimension is now the angle of the circle and the horizonal dimension is the distance from the centre point.

How to read trees. To understand how trees represent evolution, imagine the tree shown here beginning as a single lineage and growing outwards in a branching pattern over time (click the button to view the animation). That first lineage represents the old

Tips for tree reading. While evolutionary trees are a useful way of conveying complex information in a visual format, they are also frequently misunderstood. To avoid the most common confusions, keep the following hints in mind when you see a phylogenetic