The 'MARK MODE' allows you to mark and unmark individual species, or all species of a subtree.
Click on the <MARK> button (first button in the left column) of the main window or the 'F2' key on the keyboard to activate the 'MARK MODE'. In the latter case, the cursor has to be placed within the tree display area.
Mark single species:
Move the cursor to any terminal branch or the left part of the information displayed at the terminal node and press the left mouse button.
Mark all species of a subtree:
Move the cursor to any position along the edge defining the subtree and proceed as described above.
The subtree-defining branch is that located closest to the indicated root (open square) of the whole tree directly or indirectly connected to all branches of the subtree.