Nepenthes inermis was first collected on September 7, 1918, by H. A. B. Bünnemeijer on Mount Talang, at an altitude of above sea level. Two further collections were made by Bünnemeijer on Bukit Gombak on November 16, 1918, at and A fourth specimen was taken on April 26, 1920, from an elevation of on Mount Kerintji. This final specimen, Bünnemeijer 9695, was later designated as the lectotype of N. inermis by Matthew Jebb and Martin Cheek.