We present flux-calibrated integrated spectra obtained at CASLEO (San Juan, Argentina) in the range 3800-6800 Å for 15 small angular diameter Galactic open clusters. Using the equivalent widths of the Balmer lines and comparing the cluster spectra with solar-metallicity template spectra of Galactic star clusters with known properties, we derive both foreground E(B-V) colour excesses and ages. Four out of the 15 studied clusters had not been the subject of previous studies so that the fundamental parameters determined in the current work turn out to be the first of their kind. For the remaining objects, we provide independent information of that derived through colour-magnitude studies. Five clusters are found to be very young (BH 121, BH 205, Bochum 14, Tr 15 and Tr 27), four moderately young (BH 133, BH 92, Pismis 23 and NGC 6268), three are Hyades-like age clusters (Ruprecht 158, BH55 and BH90), one is an intermediate-age cluster (Ruprecht 164) and two are definitely old (ESO65-SC7 and Ruprecht 159). The E(B-V) colour excesses derived for the whole sample range from ~ 0.0 in BH133 to ~ 2.4 in Tr 27, while the ages vary from ~ 3 Myr in BH121, Bochum 14 and Trumpler 27 to ~ 2 Gyr in ESO65-SC7 and Ruprecht 159. The age and reddening distributions of the present cluster sample match those of open clusters with known parameters in a100o sector centered at l = 310o.
