Our spectrum of SN 2009dc 35 d past maximum and a few comparison SNe, with days relative to maximum light indicated for each spectrum (in parentheses). From top to bottom, the SNe are the peculiar SN 2002cx (Li et al. 2003b, where we have combined their spectra from 20 and 25 d past maximum), SN 2009dc (this work), another possible SC SN Ia SN 2007if (Scalzo et al. 2010, though the spectrum shown is from our own data base), and the ‘standard normal’ Type Ia SN 2005cf (Wang et al. 2009b). Important features discussed in the text are labelled. All spectra have had their host-galaxy recession velocities removed and have been dereddened according to the values presented in their respective references.