We compare the mass distribution of central stars of planetary nebulae (CSPN) with those of their progeny, white dwarfs (WD). We use a dynamical method to measure masses with an uncertainty of 0.02 M$_odot$. The CSPN mass distribution is sharply peaked at $0.61 rm M_odot$. The WD distribution peaks at lower masses ($0.58 rm M_odot$) and shows a much broader range of masses. Some of the difference can be explained if the early post-AGB evolution is faster than predicted by the Blocker tracks. Between 30 and 50 per cent of WD may avoid the PN phase because of too low mass. However, the discrepancy cannot be fully resolved and WD mass distributions may have been broadened by observational or model uncertainties.
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