The Nepenthaceae of the Netherlands Indies
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". Danser placed "N. rajah" in the "Regiae" (Latin: pl. of "rēgia": royal). The "Regiae" clade as proposed by Danser is shown in the adjacent table.