Thetaxonomy ofNepenthes has been revised several times during the nineteenth and twentieth centuries.
The first subgeneric division of theNepenthes was made byJoseph Dalton Hooker in his 1873 monograph, "Nepenthaceae". Hooker distinguishedN. pervillei from all other taxa based on its seeds, which lack the appendages typical of mostNepenthes. He placed it in themonotypicsectionAnourosperma. 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 byGünther Beck von Mannagetta und Lerchenau in "Die GattungNepenthes". Beck kept the two sections created by Hooker, but dividedEunepenthes into three subgroups:Apruinosae,Pruinosae, andRetiferae.
Nepenthes taxonomy was once again revised in 1908 byJohn Muirhead Macfarlane in his own monograph. Oddly, Macfarlane did not name the groups he distinguished. His revision is generally not considered to be a natural division of the genus.
In 1928,B. H. Danser published his seminal monograph, "The Nepenthaceae of the Netherlands Indies", in which he dividedNepenthes into sixclades, based on observations of herbarium material. The clades were: theVulgatae,Montanae,Nobiles,Regiae,Insignes andUrceolatae.Regiae appears to reflect the relationships of its members quite well, although the same cannot be said for the other clades. Despite this, Danser's classification was undoubtedly a great improvement on previous attempts.
Danser classifiedNepenthes as follows:
Vulgatae
Montanae
Nobiles
Regiae
Insignes
Urceolatae
The taxonomic work of Danser (1928) was revised byHermann Harms in 1936. Harms dividedNepenthes into three subgenera:Anourosperma Hook.f. (1873),Eunepenthes Hook.f. (1873) andMesonepenthes Harms (1936) (Latin:meso: middle; "middle"Nepenthes). TheNepenthes species found in the subgeneraAnourosperma andMesonepenthes differ from those in theVulgatae, where Danser had placed them. Harms placed the great majority ofNepenthes species in theEunepenthes;Anourosperma was amonotypic subgenus, whileMesonepenthes contained only three species. He also created an additional clade, theDistillatoriae (afterN. distillatoria).
