The 3D analysis (x, y, t) of the granulation intensity field (11-hour time sequence from Swedish Vacuum Solar Telescope on La Palma, Canary Islands), demonstrated that the granules in the phostosphere are organized in ``Trees of Fragmenting Granules" (TFGs). A TFG consists of a family of repeatedly splitting granules, issued from one granule at its beginning. A striking result is that TFGs can live much longer (up to 8h10) than individual granules (10 mn). When averaged in time, such long-lived TFGs can be identified to the mesogranules. We also found a correlation between the network and the spatial distribution of TFGs.