Montage of spectra of OB supergiants. Template spectra with classifications from Hanson et al. (2005) and Clark et al. (2018a) overplotted in red. It is important to note that hot pixels around 2.080 μm – nearly coincident with the C IV 2.079 μm lines – in the spectrum of CXOGC J174537.3-285354 were artificially removed; we suspect the anomalously narrow component of the Brγ photospheric profile is also spurious. Likewise the broad absorption feature centred on ∼2.1 μm in the spectrum of P95 is also artificial.