Observed profiles for the interstellar lines of CH⁺, CH, and K i in sightlines probing the Upp Sco region. HD numbers correspond to those given in Table 1. In the bottom panel the weaker K i doublet line at 7699 Å is over-plotted (thick solid line) on top of the stronger (telluric contaminated) K i doublet line at 7665 Å. The Ca i and CN lines are included only if potentially detected. The CH and CH⁺ lines are shown for all lines-of-sight. The stronger CH⁺ line at 4232 Å is over-plotted (thick solid line) on top of the 3957 Å line.