P. simensis is a disjunct, heavily farinous species found in Ethiopia and may be considered a subspecies of P. verticillata but with broader bracts, shorter corolla tube and calyx less divided. The past taxonomy of this species is mixed up with P. verticillata (see Pflanzenr. reference above). There are possible crossability barriers with P. verticillata so I have kept it at species status for the present. Information on current research into this species would be welcome.