Danser's Monograph on Nepenthes: Nepenthes decurrens

10. Nepenthes decurrens MACF., Kew Bull., 1925, p. 35 (1925).

Icon: nostra 3.

Folia mediocria petiolata, lanceolata, nervis longitudinalibus utrinque 5-6, vagina in alas 2 basi peltatas decurrente ; ascidia rosularum et inferiora ignota ; ascidia superiora magna, tubulosa v. infundibuliformia ; parte inferiore costis 2 prominentibus, os versus alis 2 fimbriatis ; peristomio expanso, 25-60 mm lato, costis c. 1 mm distantibus, dentibus vix longioribus quam latis ; operculo ovato, facie inferiore plana v. prope basin obtuse carinata ; inflorescentia racemus longus pedicellis longis fere omnibus 2-floris ; indumentum in caulibus foliisque fere 0, in ascidiis adpressum parcum in inflorescentiis tenue densum ferrugineum.

. Fig. 3. Nepenthes decurrens (HEWITT 100), 1/2 x.

Stems climbing, 15 to 20 mm thick, triangular, with long internodes, each internode with 3 pairs of decurrent wings, which are peltate at the base. Rosettes and basal parts of the stems unknown. Leaves of the climbing stems coriaceous, petiolate, lanceolate, up to 60 cm long, 8 to 10 cm broad, acute, gradually attenuate into the wings of the petiole, decurrent on the stem as 2 wings to almost the 3rd internode ; the midrib sharply keeled beneath, the pennate nerves very oblique near the midrib, transverse towards the margin, the longitudinal nerves 5 or 6 on each side, originating from the basal 1/3 part of the midrib, running parallel in the outer 3/5 of the lamina ; tendril 30 to 45 cm long, triangular and 2 to 2 1/2 mm thick near the leaf, cylindrical and up to 8 mm thick near the pitcher. Upper pitchers infundibulate in the lower part, almost tubulose for the rest, 20 to 30 cm high, 5 to 6 cm wide in the upper part, with 2 prominent ribs in the lower part, with 2 fringed wings in the upper part, the wings up to 3 mm broad, the fringe segments up to 7 mm long ; mouth almost horizontal on the wing side, strongly elevated towards the lid ; peristome expanded, 25 to 60 mm broad on the sides, narrower in front, undulate at the outer margin, the ribs less than 1 mm apart at the inner margin, more than 1 mm at the outer margin, the teeth on the inner margin once to twice as long as broad, connected by an entire margin on the back ; inner surface of the pitcher wholly glandular, with minute overarched glands, 2000-2500 glands on 1 cm2, sometimes below the lid a small eglandular part, lid ovate, up to 12 cm long, up to 8 cm broad, with a low and very obtuse keel on the underside of the midrib, on this keel and towards the margin without glands, between these parts glandular ; spur gradually ascending from the back rib of the pitcher, the free part 2 to 5 mm long, attenuate. Male inflorescence unknown. Female inflorescence a raceme, up to 100 cm long (the peduncle inclusive ?), the axis up to 45 cm long, 1 to 1 1/2 cm thick, the pedicels long, most of them 2-flowered. Tepals elliptical. Ovary surrounded by a disk. Fruit 25 to 30 mm long, lanceolate, shining, surrounded at the base by the persistent disk ; seeds up to 15 mm long, yellow. Indumentum on the young stems dense, disappearing in the adult state ; leaves glabrous when adult, with brown points on the underside ; tendril glabrous, with brown points ; pitchers sparingly covered with appressed hairs ; peduncle and axis of the inflorescence sparingly haired or glabrous when adult, the tepals outside near the margin and the ovary brown-pubescent. Colour in herbario fallow-dun, the pitchers more reddish. (Description after that of MACFARLANE in his monograph, completed with help of the 2 pitcher-bearing leaves in H. S. M.)

BORNEO. Sarawak: Baram, HEWITT 100, H. S. M. (0) ; type number of N. decurrens MACF.; doubtful specimen: 1892, EVERETT, H. S. M. (0) ; without habitat, but probably from Sarawak ; cfr. N. Northiana.

I have seen type material of this species in the Herbarium of the Sarawak Museum: 2 pitcher-bearing leaves, torn from the stem in such a way, that the manner, in which they are inserted on it, is no longer visible.

The pitchers show a great resemblance with those of the drawing of N. Northiana in The Gardeners' Chronicle, 1881, 2, between p. 724 and 725. This drawing shows 2 keels on the lid and wings over the whole pitchers, even over the curved part, but these are insignificant differences. According to the descriptions, the stems of N. Northiana are less thick than those of N. decurrens, and the leaves are sessile, but this too is not so important a difference as it seems. The most important difference is in the inflorescences. N. Northiana has a loose-flowered triangular raceme, with 2 to 3 mm long pedicels, N. decurrens has a long and coarse raceme, with long pedicels (the description of both inflorescences is very imperfect). Therefore it is impossible for me to determine the 3 above mentioned inferior pitchers, I found in the Sarawak Herbarium, and collected by EVERETT in 1892. This Mr. EVERETT may be the same which collected N. Northiana for MARIANNE NORTH and therefore it seems possible that the 3 pitchers mentioned are the basal ones of the latter species. They are ovate-ellipsoidal, resp. 23, 24 and 26 cm high, 10, 11 and 10 cm wide, widest about, or somewhat below the middle ; the peristomes are as in N. decurrens, resp. 3, 4 and 2 1/2 cm broad, the mouth is very oblique, occupying about half the height of the pitcher, the lid has one median keel, but is crumpled, and the form, though not well visible, seems to be that of N. decurrens.

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