We present a study of the metallicity and age of the globular clusters system of M49 ( NGC 4472 ) , the most luminous galaxy in the Virgo cluster .
We measure Lick indices for 47 GCs in M49 from LRIS/Keck spectra and establish their metallicity parameters qualitatively in comparison to the Galactic GCs and to published data for 150 M87 GCs .
We then compare our measurements with the predictions of models for the integrated light of old single burst stellar systems by ( ) 
and by ( ) .
We find that the metallicity of the M49 GC system spans the range from [ Fe/H ] _ { Z } = -2.0 to +0.4 dex .
We show that the metallicity and age parameters for these two GC systems are basically identical , except that the M49 GCs reach slightly higher metallicities than do those of M87 .
We find that the GCs of both of these giant elliptical galaxies are \alpha -enhanced by a factor of about two above the Solar value , as is also true of the Galactic GCs .
Thus the most metal rich GCs in M49 reach [ Z/H ] \sim +0.8 dex , comparable to that of M49 itself .
While adoption of the \alpha -enhanced models of ( ) has eliminated most of the previous discrepancies with observations , the most metal rich M49 GCs have NaD lines which are still considerably stronger than those predicted by any model , and there are still issues involving the metallicity scale of these models .
We find that in the mean , the M49 GCs are at least 10 Gyr old .
However , the grids of models we used differ in how they treat the horizontal branch , and this perceptibly affects the predicted H \beta index .
Hence our current incomplete understanding of the role of the horizontal branch limits our ability to derive a more detailed distribution for the ages of the GCs in M49 and in M87 .