Spectral type to the bandhead depth of TiO 8859Å. The colour indicates the luminosity class. The shape indicates their origin, circles are from the SMC survey, squares are from the LMC survey, diamonds are standards, inverted triangles are from the Perseus arm survey. This bandhead rises at M1, growing with increasing SpT. However, at approximately M7 the bandhead is saturated, and starts to decrease with increasing SpT because of the erosion caused by the TiO bandhead at 8432Å. The error bars indicate the median uncertainty for the bandhead depth, and the estimated uncertainty for SpT from GDN2015.