Nepenthes bicalcarata

Nepenthes bicalcarata

Synonymy

Nepenthes bicalcarata Hook.f. in de Candolle, Prodr. 17: 97 (-98). 1873 sec. Cheek & Jebb 2001
    • Lectotype: Malaysia, Borneo, Sarawak, Lawas River, H. Low s.n. (K).
    • Isotype: Malaysia, Borneo, Sarawak, Lawas River, H. Low s.n. (K).
  • =Nepenthes dyak S.Moore in J. Bot. 18: 1, t. 206. 1880 syn. sec. Cheek & Jebb 2001

Other sources

Danser, B.H. 1928: – Bull. Jard. Bot. Buitenzorg, sér. 3, 9: 270
Kurata, S. 1976: Nepenthes of Mt Kinabalu, Sabah: 37, t. 8
Clarke, C.M. 1997: Nepenthes of Borneo: 68, f. 43 & 44
Beccari, O. 1886: Malesia 2: 231, t. 55
Nepenthes dyak S.Moore: Burbidge, F.W.T. 1882: – Gard. Chron. 1: 56 (as Nepenthes dyak S.Moore)
Jebb, M.H.P. & Cheek, M.R. 1997: A skeletal revision of Nepenthes. – Blumea 42(1): 1-106: 24
Nepenthes dyak S.Moore: Beccari, O. 1886: Malesia 3: 1 (as Nepenthes dyak S.Moore)
Phillipps, A. & Lamb, A.L. 1996: Pitcher Plants of Borneo: 70, f. 41

Description

Terrestrial climber up to 15 m tall. Stem terete, c. 1.8 cm diam., sometimes hollow with small circular entrance holes cut by ants, internodes 0.5-8 cm long. Leaves thickly chartaceous, petiolate, oblong-lanceolate, 20-65 by 6-14 cm, apex acute to truncate and emarginate, occasionally peltate, base attenuate; petiole narrowly winged, 4-12 cm long, clasping the stem for 3/4 of its circumference, petiole wings sometimes decurrent to next node, usually large rimmed nectaries present on lower surface of pet-iole immediately adjacent to stem. Longitudinal nerves 10 or more on each side of the midrib. Pennate nerves patent, numerous, distinct almost to leaf margin. Tendril of lower pitcher swollen, to 12 mm thick, and with a thin-walled spot which is usually hollowed and inhabited by an ant colony, entrance hole facing towards pitcher surface; tendril of upper pitcher only once coiled, coil in contact with the dorsal surface of pitcher, and it is at this point that the entrance hole to the hollow tendril lies. Lower pitchers globose, to 13 by 6.5 cm; with 2 fringed wings to 2.3 cm broad, fringed elements to 1.2 cm long, 0.5-4 mm apart; nectaries scattered on pitcher surface, especially dorsally, on ventral wings and on tendril; mouth suborbicular, straight and almost horizontal at front, rising abruptly at rear and forming a stout vertical or overarching column; peristome with outer edge cylindrical, c. 0.4 cm wide, inner edge flat, 1-2 cm wide, ribs 0.2-0.5 mm apart, inner margin with teeth c. 0.6 mm long, with a pit between each tooth; the apical most 10-12 ribs of the column drawn out into a pair of long downward curving acute thorns 1-2.5 cm long; lid reniform, much wider than long, 3.5-6 by 4.7-6 cm, glands thinly bordered, circular, c. 0.3 mm diam., densest towards the two sides, ± absent towards centre and near junction with pitcher; spur simple, flattened, recurved, glandular, 10-20 mm long. Upper pitchers ovoid-cylindrical, slightly narrowed towards mouth, to 13 by 6 cm, with 2 prominent ribs, these sometimes minutely winged near peristome; peristome and spur as in lower pitchers, lid often larger still, to 4 by 10 cm. Male inflorescence to 1 m long; peduncle 0.6 cm diam. at base; partial peduncles to 10 cm long, fasciculate,(1-)4-15-flowered, sometimes with nectaries near the base; pedicels to 2.5 cm long; occasionally with a bract on the lower half of the basal partial peduncles; tepals suborbicular, 5 by 4 mm; androphore 1.5-2 mm long; anther head 1 by 1.5 mm. Fruit with valves to 3 by 0.5 cm, lanceolate. Seed not seen. Indumentum sparse on leaves and stem, dense on pitchers and inflorescence; on the latter of two kinds, a dense short pubescence, and scattered longer hairs of 1-2 mm. Colour of pitchers green with orange to red flush from the indumentum, peristome green, rarely red; lid yellowish above, often deeper red or purple below, especially towards margin; tepals deep purple, almost black.A

Notes

Nepenthes bicalcarata is not easily confused with any other species of the genus: the huge peristome thorns formed from united ribs, the reniform lid which is broader than long, and the ant-hollowed tendrils and stems, are each features unique to this species. The paniculate inflorescence has fasciculate partial peduncles similar to those of the Madagascan species (N. madagascariensis and N. masoalensis).
The tendril of the pitcher is nearly always hollowed out and occupied by small red ants (Camponotus schmitzii). The ants are said to recover prey items from the pitcher fluid. Numerous nectar glands are found scattered on the stem, upper midribs and tendrils, and the spur is also often densely glandular. The long lid-column and the recurved thorns may comprise parts of the mechanism of prey capture, rather than the fanciful protective role suggested by Burbidge (Gard. Chron. (28/2/1880) ).
The upper pitchers of this species are often surprisingly small relative to the large leaf blades. This may be an adaptation to the somewhat shady sites that this species favours.A

Distribution (General)

Borneo: NW Kalimantan, Sarawak, Brunei, SW Sabah.A

Habitat

Locally common in peat-swamp forest dominated by Shorea albida, also occasionally in heath forest on white sand soils; sea level to 950 m.A

Bibliography

A. Cheek, M.R. & Jebb, M.H.P. 2001: Flora Malesiana - Nepenthaceae, Series I, Volume 15

Specimens

CountryDateCollector + collecting numberHerbariaTypeScanDerivatives
MalaysiaLow, H. s.n.K(2)
Citation: Malaysia, Borneo, Sarawak, Lawas River, H. Low s.n.

Specimen summary: K
Isotype of Nepenthes bicalcarata Hook.f.