Initial abundances (corrected for atomic diffusion and dredge-up) of lithium, compared to the anticorrelation elements magnesium (left), sodium (middle) and aluminium (right). The dotted line and shaded region refer to the predicted primordial abundance based on the CMB-calibrated BBN predictions (see text). The faintest (V> 16.8) stars have been excluded from the comparison. Different coloured symbols correspond to the chemical populations deduced from the cluster analysis.