An object of class \code{"yule"} (see \code{\link{yule}}).
}
\author{Emmanuel Paradis}
+\references{
+ Hubert, N., Paradis, E., Bruggemann, H. & Planes, S. (2011) Community
+ assembly and diversification in Indo-Pacific coral reef
+ fishes. \emph{Ecology and Evolution}, \bold{1}, 229--277.
+}
\seealso{
\code{\link{branching.times}}, \code{\link{ltt.plot}},
\code{\link{birthdeath}}, \code{\link{yule}}, \code{\link{yule.cov}},