The limits of Pedicularis L. ser. Megalanthae (Prain) Bonati (Orobanchaceae) are revised. The series, typified by Pedicularis megalantha D.Don, is restricted to seven species chiefly inhabiting the eastern Sino-Himalayan region. Authorship of the name Megalanthae at series rank is ascribed to Bonati (Mém. Soc. Bot. France 18: 13, 1910) because the groups recognised by Prain in 1890, that have been traditionally regarded as series, are in fact rankless. Two species of the NW Himalayan region, Pedicularis bicornuta Klotzsch and P. elephantoides Benth., are removed from P. ser. Megalanthae as they differ significantly from the eastern species in their floral morphology. These species are considered sufficiently distinct to warrant recognition as the new series Pedicularis ser. Bicornutae R.R.Mill. This new series is provisionally assigned to Pedicularis sect. Phanerantha H.L.Li. Pedicularis bicornuta, whose holotype is destroyed, and P. eximia G.Watt are lectotypified. The recently published Pedicularis bicornuta var. adenocalyx R.R.Mill includes the lectotype and much, but not all, material previously assigned to P. eximia.