List of Nepenthes clades

The taxonomy of "Nepenthes" has been revised several times during the nineteenth and twentieth centuries.
Nineteenth century.
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.
"Nepenthes" taxonomy was once again revised in 1908 by John 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 divided "Nepenthes" into six clades, based on observations of herbarium material. The clades were: the "Vulgatae", "Montanae", "Nobiles", "Regiae", "Insignes" and "Urceolatae". "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 classified "Nepenthes" as follows:
Vulgatae
Montanae
Nobiles
Regiae
Insignes
Urceolatae
The taxonomic work of Danser (1928) was revised by Hermann Harms in 1936. Harms divided "Nepenthes" into three subgenera: "Anourosperma" Hook.f. (1873), "Eunepenthes" Hook.f. (1873) and "Mesonepenthes" Harms (1936) (Latin: "meso": middle; "middle" "Nepenthes"). The "Nepenthes" species found in the subgenera "Anourosperma" and "Mesonepenthes" differ from those in the "Vulgatae", where Danser had placed them. Harms placed the great majority of "Nepenthes" species in the "Eunepenthes"; "Anourosperma" was a monotypic subgenus, while "Mesonepenthes" contained only three species. He also created an additional clade, the "Distillatoriae" (after "N. distillatoria").