1	Upper corolla lip with trichome transparent to white	2
–	Upper corolla lip with trichomes brown to black	4
2	No branched trichomes on leaf and bract	P.henryi
–	With branched trichomes on leaf and bract	3
3	Floral bracts with branched trichomes, bracts linear to lanceolate	P.bracteosa
–	Floral bracts with simple trichomes only, bracts needle-like to subulate	P.rotata
4	Floral bracts with trichomes brown to black	5
–	Floral bracts with trichomes transparent to white	6
5	Floral bracts with black simple trichomes, no branched trichomes	P.tibetica
–	Floral bracts with brown simple and branched trichomes	P.milingensis
6	Floral bracts less than 1 cm long, with branched trichomes	P.breviflora
–	Floral bracts more than 1 cm long, with only simple trichomes	7
7	Flower purple	P.nyalamensis
–	Flower white	P.macrophylla