It used to be known only from a single dried herbarium specimen[3] and is the sole recognised species in the genus Nepenthes of which the pitchers are unknown.

[4] The habitat of N. mollis is listed as dense forest on a steep slope at an elevation of 1,800 m.[5] The species is only known from Mount Kemul, the type locality, although a wider distribution is possible, as several higher neighbouring mountains remain unexplored.

[1] Nepenthes mollis has only been collected once, on October 17, 1925 by Frederik Endert on Mount Kemul[note a] in East Kalimantan.

[8][note b] Nepenthes mollis was formally described in 1928 by B. H. Danser in his seminal monograph "The Nepenthaceae of the Netherlands Indies".

The male inflorescence is densely covered with flowers and is described by Danser as "not robust" and "at last seemingly lateral".

A similar, though longer and much denser, covering of hairs exists on younger parts of the stem and near the axils, on the underside and top of the midrib, and on the undeveloped pitchers.

The underside of the leaves is densely hirsute and bears short branched and longer unbranched, softer hairs.

[5] Danser placed N. mollis in the clade Regiae, together with 14 other species: N. boschiana, N. burbidgeae, N. clipeata, N. ephippiata, N. fusca, N. klossii, N. lowii, N. maxima, N. oblanceolata (now considered a junior synonym of N. maxima), N. pilosa, N. rajah, N. stenophylla, N. truncata, and N. veitchii.

With regards to the classification of N. mollis, Danser wrote:[5] The taxonomic place of N. ephippiata and N. mollis is uncertain, as the pitchers are unknown, but the coarse stems and leaves, the yellowish colour of the former and the abundant hirsute indumentum and red-brown colour of the latter leave hardly any doubt whether both are Regiae.Matthew Jebb, in his account of Nepenthes in New Guinea, suggests that N. mollis "may have a similar growth-form to that of N. ampullaria, with the climbing stems rarely, if ever, producing pitchers".

sp.,[note d] collected on Mount Lumarku at an altitude of 1,700 m in "tall dense forest on an exposed ridge line".

Based on close morphological similarities and plausible geographical overlap, he suggests that the unidentified taxon may represent N. mollis.

The degree of supposed leaf decurrence and the bracts on the pedicels can be explained by natural variation within the range of this species.

(G. Lumarku, G. Murud, Meligan Range) in the northwest and N. mollis (G. Kemul) in the southeast to provide a link between the two.Salmon also notes that the growth habit of N. sp.

[13] An editor's note by Jan Schlauer accompanying Salmon's article cautions that live specimens from the type locality of N. mollis must be examined before the two taxa are united.

[12] The identity of the specimens from G. Lumarku with N. mollis should be proven by comparison with authentic pitchered material from G. Kemul.

Unless this is done, the data above cannot be taken as an emendation of Danser's original description of N. mollis but are only referring to north Bornean plants without doubt.The unidentified species from Mount Lumarku was formally described as N. hurrelliana in 2003 by Martin Cheek and Anthony Lamb.

[14] Its natural range is now known to cover northern Sarawak, Brunei, and southwestern Sabah, although it has not been recorded from Kalimantan.

Recent monographs on the genus maintain that N. mollis has not been relocated in the wild since Endert's original collection.

[17] Folia mediocria sessilia, lamina lanceolata v. spathulato-lanceolata, nervis longitudinalibus utrinque 0 v. 1, raro 2, basi in alas 2 sensim angustatas decurrente; ascidia ignota ; inflorescentia racemus magnitudine mediocria, pedicellis inferioribus c. 12 mm longis, omnibus 2-floris ; indumentum copiossisimum, in foliis pagina superiore parcius albidum, in foliorum pagina inferiore et caulibus densum obscure badium, in partibus iuvenilibus et inflorescentiis floribusque densissimum obscure badium.