  We present a new multiwavelength analysis of the Coma cluster subclustering
based on recent X-ray data and on a compilation of nearly 900 redshifts. We
characterize subclustering using the Serna&Gerbal (1996) hierarchical method
which makes use of galaxy positions, redshifts, and magnitudes, and identify 17
groups. One of these groups corresponds to the main cluster, one is the well
known group associated with the infalling galaxy NGC4839 and one is associated
with NGC4911/NGC4926. About one third of the 17 groups have velocity
distributions centered on the velocities of the very bright cluster galaxies
they contain (magnitudes R<13). In order to search for additional
substructures, we make use of the isophotes of X-ray brightness residuals left
after the subtraction of the best-fit beta-model from the overall X-ray gas
distribution (Neumann et al. 2003). We select galaxies within each of these
isophotes and compare their velocity distributions with that of the whole
cluster. We confirm in this way the two groups associated, respectively, with
NGC4839, and with the southern part of the extended western substructure
visible in X-rays. We discuss the group properties in the context of a scenario
in which Coma is built by the accretion of groups infalling from the
surrounding large scale structure. We estimate the recent mass accretion rate
of Coma and compare it with hierarchical models of cluster evolution.
