P. reidii is a high alpine species similar to P. wigramiana but distinguished from the later by the annulate corolla and the emarginate, but not toothed, corolla lobes. P. reidii var williamsii is a larger plant from West-Central Nepal. The variety was collected as a blue-flowered plant but the color can vary from white to blue as can the species, so that it is difficult to distinguished the two.