Figure 4.

Diagrams and notation for three special cases of calibration. a) Calibrating the parent of a clade of size $n$. b) Calibrating a nested clade of size $n$ and the root with a total of $n+m$ taxa. c) Calibrating two nested clades of size $n$ and $n+m$ taxa in a $n+m+l$ taxa tree ($l>0$).