Same as Fig. 3, for giant stars in ten different metal-poor clusters (five each in the upper and lower panels). The metallicities are taken from the following publications: Friel & Janes (1993); Gratton & Contarini (1994); Pasquini et al. (2001); Friel et al. (2002); Carraro et al. (2004); Yong et al. (2005); Sestito et al. (2006, 2008); Santos et al. (2009, Table 3); Friel et al. (2010); Carrera & Pancino (2011); Yong et al. (2012); and Jacobson & Friel (2013). For star identifications and corresponding reference T_eff see Table 5. The bar below the legend in the upper panel indicates the mean of the uncertainties for the individual [Fe/H] values quoted in the high-resolution publications (ranging from 0.04 to 0.3 dex).