Herbarium specimens informally named N. junghuhnii by Macfarlane were collected by Junghuhn in the Batak region of North Sumatra, near Lake Toba. The specimens of N. singalana that Ridley used to describe N. junghuhnii originated from a collection by Harold Ernest Robinson and Cecil Boden Kloss on Mount Kerinci, in the Sumatran province of Jambi.