The first subgeneric division of the
Nepenthes was made by
Joseph Dalton Hooker in his 1873 monograph, "
Nepenthaceae". Hooker distinguished
N. pervillei from all other taxa based on its seeds, which lack the appendages typical of most
Nepenthes. He placed it in the
monotypic section Anourosperma. All other species were subsumed in the second section,
Eunepenthes. A second attempt to establish a natural subdivision within the genus was made in 1895 by
Günther Beck von Mannagetta und Lerchenau in "
Die Gattung Nepenthes". Beck kept the two sections created by Hooker, but divided
Eunepenthes into three subgroups:
Apruinosae,
Pruinosae, and
Retiferae. ==Twentieth century==