Observed: 20th June 2015
Added: 25th June 2015
The corolla has four lobes which rules out labalis and leaves us with glabella, similis or ericoides.
The leaves are 4-nate which doesn't really help to narrow it down.
It's not similis which has long white hairs on the caly, whereas glabella and ericoides have short white hairs.
Therefore either glabella or ericoides.
The bract and bractioles of ericoides are adpressed to the corrolla, whereas for glabella the bract is on the main stem and the bractioles are either minute or absent.
For glabella the ridges on the calyx tube alternate with the calyx lobes.