Charge partitions and distributions of fragments emitted in multifragmentation of fused systems produced in central collisions are studied over the incident energy range 32-50 MeV per nucleon. Most of the charged products are well identified thanks to the high performances of the INDRA 4pi array. Supported by dynamical calculations, charge correlations are used t$ evidence, or not, spinodal instabilities and consequently the liquid-gas coexistence region over the considered incident energy range. It was claimed in the last few years that mass/charge distributions should follow a power law behavior in the coexistence region. The Z distributions measured are discussed. A first attempt is made to derive in which Z region the border between liquid and gas parts is located.