add.scale.bar: Add a Scale Bar to a Phylogeny Plot
Description
This function adds a horizontal bar giving the scale of the branch
lengths to a plot of a phylogenetic tree on the current graphical
device.
Usage
add.scale.bar(x, y, length = NULL, ask = FALSE, ...)
Arguments
Details
By default, the bar is placed in a corner of the graph depending on
the direction of the tree. Otherwise both x and y must
be specified (if only one is given it is ignored).
The further arguments (...) are used to format the text. They
may be font, cex, col, and so on (see examples
below, and the help page on text).
The function locator may be used to
determine the x and y arguments.