  Multivariate clustering in astrophysics is a recent development justified by
the bigger and bigger surveys of the sky. The phylogenetic approach is probably
the most unexpected technique that has appeared for the unsupervised
classification of galaxies, stellar populations or globular clusters. On one
side, this is a somewhat natural way of classifying astrophysical entities
which are all evolving objects. On the other side, several conceptual and
practical difficulties arize, such as the hierarchical representation of the
astrophysical diversity, the continuous nature of the parameters, and the
adequation of the result to the usual practice for the physical interpretation.
Most of these have now been solved through the studies of limited samples of
stellar clusters and galaxies. Up to now, only the Maximum Parsimony
(cladistics) has been used since it is the simplest and most general
phylogenetic technique. Probabilistic and network approaches are obvious
extensions that should be explored in the future.
