Nepenthes muluensis

Nepenthes muluensis


Nepenthes muluensis M.Hotta in Acta Phytotax. Geobot. 22: 7, f. 2. 1966 sec. Cheek & Jebb 2001 wfo-0000381554
      Holotype: Borneo, Sarawak, Mt Mulu, western ridge, alt. 1900 – 2400 m, 18 Mar 1964, Hotta 14791a. (KYO; isotype: L)
  • =Nepenthes sarawakiensis J.H.Adam & Wilcock in Sarawak Mus. J. 43: 291. 1992 syn. sec. Cheek & Jebb 2001 wfo-0000381457
    • Holotype: Borneo, Sarawak, G. Mulu, alt. 2320 m, 8 Dec 1987, 2403 (UKMS; isotype: SAR)

Other sources

Phillipps, A. & Lamb, A.L. 1996: Pitcher Plants of Borneo. 115, f. 61 & 62
Jebb, M. H. P. & Cheek, M. R. 1997: A skeletal revision of Nepenthes. – Blumea 42(1): 1-106. p 66


Terrestrial climber 1-3 m tall. Rosette and short stems unknown, climbing stems slightly flexuose, terete or 2-ridged, (2-)3(-4) mm diam., internodes 1-2 cm long. Leaves thinly coriaceous, sessile, glossy above, those of rosettes with bases semi-amplexicaul, those of climbing stems narrowly oblanceolate-oblong to lanceolate-oblong, 4.2-6.5 by 1.1-1.7(-2) cm, apex acute to rounded, not peltate, base slightly attenuate, clasping the stem for 1/3-1/2 its circumference, not decurrent. Longitudinal nerves 3 or 4 on each side of the midrib, scattered fairly evenly, fairly conspicuous above and below. Pennate nerves numerous, patent, straight, fairly conspicuous above and below. Lower pitchers not seen but reported similar to those of N. tentaculata (Clarke in Nepenthes of Borneo (1997) 109). Upper pitchers subcylindrical, the basal 1/4 obcampanulate, gradually becoming slightly constricted in the middle and then dilating slightly at the mouth, (5.2-)6.8-8.5(-9) by (1.4-)1.6-2.2(-2.5) cm, with two narrow, non-fringed wings 0.3-0.7 mm wide; mouth elliptic to broadly elliptic, slightly concave, oblique, peristome rounded, 0.8-1 mm wide, ribs indistinct, c. 0.2 mm apart, outer edge entire, inner edge without teeth; lid orbicular to transversely elliptic, (1.1-)1.5-2.1 by (1.4-)1.7-2.4 cm, apex rounded to truncate, base cordate to truncate, lower sur-face lacking appendages, midrib forking 3-4 mm before the apex; nectar glands conspicuous, sparsely scattered over the whole surface, bordered, circular, 0.1-0.2 mm diam.; upper surface lacking tentacles; spur stout, entire, dorsiventrally flattened, unbranched, 2.5-3 by 1 mm, apex rounded. Male inflorescence 9.5 by c. 1.8 cm; peduncle 1.5 cm long, 1.5 mm wide at base; partial peduncles 1-flowered, bracts absent; pedicels c. 50, 4-6 mm long; tepals elliptic, 3-3.5 by 1.5 mm, apex obtuse; androphore 2-2.5 mm; anther head 1.5 by 1.5 mm. Infructescence c. 8 cm long, with 11-13 fruits. Fruit with valves elliptic, (13-)15-19 by 5.5-7 mm. Seeds c. 90 per fruit, fusiform, 10-12 by 0.6-1 mm. Indumentum of sessile red glands on stem and lower surface of blade; midrib conspicuously pubescent with erect orange-brown simple hairs c. 0.2 mm long; pitcher, including spur, glabrous; inflorescence from peduncle to lower surface of tepals and base of androphore with scattered appressed coppery simple hairs 0.1-0.2 mm long. Colour on drying matt black; live plants with stems black or dark red, “pitchers ranging from dark red to almost black, with cream blotching. Lid of pitcher creamy white, often tinged pink. Lip yellow. Flower pale green maturing brown. Fruit like two pyramids end to end, upper half yellowish, lower half red.” (Lewis 354).A


Nepenthes muluensis is a distinct, slender species not easily confused in the climbing stems and upper pitchers with the only other small highland species in Borneo, N. tentaculata. Nepenthes muluensis differs in its non-perfoliate-adnate leaves, entire, short spur and orbicular to transversely elliptic lid. The lid and peristome are usually a delicate whitish green or white in colour, contrasting strikingly with the pitcher which is predominantly purple and only lightly blotched with white.
The lower pitchers are reported by Clarke in Nepenthes of Borneo (1997) 109, f. 37 & 73 as being almost identical with those of N. tentaculata, with bristles around the edge of the upper surface of the lid. Thus we conclude that the purported hybrid between N. tentaculata and N. muluensis, N.sarawakiensis from Mulu, is probably merely a young plant of N. muluensis. Whether the leaves of the short stems are perfoliate-adnate, as characteristic of that species group, is not reported, but this species pre-sumably belongs here. The few-flowered, diminutive, ebracteate raceme and the inconspicuously ridged peristome of N. muluensis are all characters seen in the N. tentaculata group. Unfortunately all specimens available to us show only the climbing stems and upper pitchers. This is also the case with N. glabrata of Sulawesi to which N. muluensis is extremely similar, sharing many unusual characters not otherwise seen in the N. tentaculata group, such as the plants being glabrous in most parts, in the white lid and white and red pitcher, in the orbicular to transversely elliptic lid with its unusual nervation, the short, entire spur, the conspicuous bordered nectar glands and the androphore, being hairy at the base. Nepenthes glabrata differs in its pitchers being more broadly cylindrical, lacking a campanulate base and in having wings twice as broad as in N. muluensis. Its inflorescence indumentum is white, not coppery, and its spur is hairy. Moreover its leaves are twice as long as those of N. muluensis and with only 1 (not 3 or 4) pairs of longitudinal nerves.
Belongs to Nepenthes sect. Tentaculatae Cheek & Jebb.A

Distribution (General)

Borneo: Sarawak (Mt Mulu, Mt Murud, Batu Lawi, and the Tama Abu Range).A


Stunted montane forest or ericoid scrub on sandstone ridges; altitude 1750-2400 m.A


A. Cheek, M. R. & Jebb, M. H. P. 2001: Flora Malesiana - Nepenthaceae, Series I, Volume 15. – Leiden: Nationaal Herbarium Nederland, Universiteit Leiden branch


CountryDateCollector + collecting numberHerbariaTypeScanDerivatives
18 Mar 1964Hotta 14791a.KYO, L
Citation: Borneo, Sarawak, Mt Mulu, western ridge, alt. 1900 – 2400 m, 18 Mar 1964, Hotta 14791a.

Specimen summary: KYO
Holotype of Nepenthes muluensis M.Hotta

Specimen summary: L
Isotype of Nepenthes muluensis M.Hotta

8 Dec 1987-empty team- 2403SAR, UKMS
Citation: Borneo, Sarawak, G. Mulu, alt. 2320 m, 8 Dec 1987, 2403

Specimen summary: SAR
Isotype of Nepenthes sarawakiensis J.H.Adam & Wilcock

Specimen summary: UKMS
Holotype of Nepenthes sarawakiensis J.H.Adam & Wilcock