Melampyrum is a genus of about 20 species of herbaceous flowering plants in the family Orobanchaceae known commonly as cow wheat.

The phylogeny of the genera of Rhinantheae has been explored using molecular characters.

[2][3] Melampyrum appears as a distant relative of other genera of Rhinantheae.

It is the sister group of two clades: (i) Rhynchocorys, Lathraea, and Rhinanthus ; and (ii) the core Rhinantheae containing Bartsia, Euphrasia, Tozzia, Hedbergia, Bellardia, and Odontites.

Melampyrum Rhynchocorys Lathraea Rhinanthus Bartsia sensu stricto (Bartsia alpina) Euphrasia Hedbergia   (including Bartsia decurva + B. longiflora) Tozzia Odontites sensu lato   (including Bartsiella   and Bornmuellerantha) Bellardia Neobartsia (New World Bartsia) Parentucellia