- As from version 1.4 of ape, the options of this function have been
- redefined, and have now default values. By default, the scale bar is
- plotted on the left bottom corner of the plot.
+ By default, the bar is placed in a corner of the graph depending on
+ the direction of the tree. Otherwise both \code{x} and \code{y} must
+ be specified (if only one is given it is ignored).