Nepenthes rajah

Nepenthes rajah


Nepenthes rajah Hook.f. in Trans. Linn. Soc. London 22: 421, t. 72. 1859, sec. Cheek & Jebb 2001 wfo-0000381453
      Holotype: Borneo, Sabah, Mt Kinabalu, alt. 1500 m, H. Low s.n. (K)

Other sources

Jebb, M. H. P. & Cheek, M. R. 1997: A skeletal revision of Nepenthes. – Blumea 42(1): 1-106. p 76
Clarke, C. M. 1997: Nepenthes of Borneo. – Kota Kinabalu: Natural History Publications. 120, f. 81-83
Phillipps, A. & Lamb, A.L. 1996: Pitcher Plants of Borneo. 129, f. 69 & 70
Danser, B. H. 1928: – Bull. Jard. Bot. Buitenzorg, sér. 3, 9. p 361
Kurata, S. 1976: Nepenthes of Mt Kinabalu, Sabah. – Sabah National Parks Trustees, Kota Kinabalu. 61, t. 19 & 20
Adam, J. H. & Wilcock, C.C. 1998: – Sarawak Mus. J. 50: 75-77. 155, f. XXIIIc.


Terrestrial shrub up to 2 m tall, sometimes scrambling. Stems terete, 15-30 mm diam. Leaves coriaceous, petiolate; blade oblong, 20-50(-80) by 9-13(-15) cm, apex rounded, peltate: midrib detaching to form tendril up to 3.2 cm from the apex, base obtuse; petiole canaliculate, 3.5-14 cm long, 1-2 cm deep, base sheathing and clasping the stem for c. 3/4 its circumference, not decurrent or auriculate. Longitudinal nerves 3(-5) each side of the midrib in the outer half. Pennate nerves numerous, running obliquely to the margin, conspicuous. Lower pitchers subellipsoid, 20-35 by 11-18 cm, with two fringed wings, 4-9 mm wide, the fringed elements c. 4 mm long, c. 2 mm apart; mouth broadly elliptic, flat, oblique at 45° from the horizontal; peristome rounded or slightly flattened, 25-35 mm wide, slightly widest towards the lid, ribs 1.5-5 mm apart, with at least 10 striae in between, inner edge dentate, teeth 3-5 mm long, outer edge with 5 or 6 folds per side, each protruding up to 1-1.5 cm; lid larger than the mouth, vaulted, oblong to obovate, 15-20 by 10-13 cm, apex truncate to rounded, base truncate-cordate, lower surface lacking appendages but with a robust keel-like midrib in the basal half, nectar glands minute, crater-like c. 0.1 mm diam; spur stout, 10 mm long. Upper pitchers rarely produced, as the lower, but infundibulate, not ellipsoid, lacking fringed elements to the reduced, ridge-like wings. Male inflorescence 60-85 cm long, peduncle 28-34 cm long, 0.6-0.7 cm diam.; partial peduncles c. 100, 9-15 mm long, 2-flowered; bracts absent; pedicels 6-9 mm long; tepals elliptic, 4-5 by 2.5 mm; androphore 2-3 mm long; anther head 1 mm long, 1.5-2 mm wide. Fruits with valves 20 mm long. Seeds unknown. Indumentum of brown spreading hairs on stem when young, absent from leaves apart from the brown woolly margin; outer lid and pitcher surface with appressed, brown simple hairs c. 0.5 mm long, glabrescent. Inflorescence, particularly the partial peduncles and pedicels, lower tepal surface and androphore, densely covered in the same hair type; infructescence with hairs persisting on fruit valves. Colour of pitchers purplish red, peristome dark purple, inner surface of pitcher and lower surface of lid green or yellow. Flowers dull greenish white, flushed maroon outside.A


Nepenthes rajah is renowned as the largest pitchered of all pitcher plants (though less well known species such as N. merrilliana and N. truncata may bear equally voluminous pitchers) and for trapping rats. The peltate leaf blade tip, oversized and vaulted lid, as well as its overall large size, make this a very distinct species. The inner peristome wall is elaborated to form three layers; these are interconnected by a series of staggered cross-walls, creating two rows of box-like compartments.A


2. Nepenthes rajah x N. burbidgeae (Nepenthes x alisaputrana J.H. Adam & Wilcock) - See under N. burbidgeae.A 1. Nepenthes rajah x N. villosa (Nepenthes x kinabaluensis Sh. Kurata ex J.H. Adam & Wilcock) - See under Nepenthes x kinabaluensis.A

Distribution (General)

Borneo: Sabah (Mt Kinabalu&Mt Tambuyukon).A


Open sites in mossy forest, on ridges or landslips, restricted to ultramafic soils; 1500-2650 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
Low, H. s.n.K
Citation: Borneo, Sabah, Mt Kinabalu, alt. 1500 m, H. Low s.n.

Specimen summary: K
Holotype of Nepenthes rajah Hook.f.