Danser's Monograph on Nepenthes: Nepenthes tobaica

45. Nepenthes tobaica DANS., spec. nova.

Icones: Trop. Nat., XVI, p. 201 (1927) habitus ; nostra 23.

Folia mediocria sessilia, lamina lineari-lanceolata, nervis longitudinalibus utrinque 0-1, raro 2, basi lata semiamplexicauli ; ascidia rosularum ignota ; ascidia inferiora parte inferiore anguste ovata, medio angustata, os versus infundibuliformia, alis 2 fimbriatis, peristomio operculum versus acuto, cylindrico, 1/2-1 mm lato, costis 1/3-1/4 mm distantibus, saepe indistinctis, dentibus fere 0 ; operculo rotundato-elliptico, facie inferiore plano ; ascidia superiora parva, e basi infundibuliformi parte inferiore paulum ventricosa, medio leviter angustata, os versus paulum infundibuliformia, costis 2 prominentibus, peristomio operculum versus acuto, cylindrico, 1/2-1 mm lato, costis 1/3-1/4 mm distantibus, saepe indistinctis, dentibus fere 0 ; operculo orbiculari v. rotundato-elliptico facie interiore plana ; inflorescentia racemus pedicellis 13-15 mm longis fere omnibus 2-floris ; indumentum in inflorescentiis et ascidiis parcum stellatum, ceterum 0.

Stems climbing, up to 5 m high, the part with adult leaves cylindrical to obtusely triangular, usually 1 to 3 mm thick, the internodes about 7 cm long ; short shoots often developed, rosettes unknown. Leaves of the short shoots and longer stems scattered, sessile, mostly 5 to 12 cm long, 0.6 to 1.5 cm broad, often involute at the margins, acute, broader than the stem at the rounded or slightly amplexicaul base ; pennate nerves running very obliquely towards the margin and irregularly reticulate, mostly invisible, longitudinal nerves mostly absent, sometimes 1, rarely 2 on each side ; tendrils of the lower leaves often shorter than the lamina, without curl, those of the upper leaves 1 to 1 1/2 times as long as the lamina, with curl. Lower pitchers almost like the upper ones, somewhat wider and with 2 distinctly fringed wings, the wings about l l/2 mm broad, the fringe segments about 1 mm long, 3/4 mm apart. Upper pitchers shortly incurved from the hanging tendril, the curve about 2 to 10 mm wide, 4 1/2 to 9 cm high, the basal part infundibuliform, then ventricose about l l/2 to 2 1/2 cm wide, narrowed in the middle to 1/2 or 2/3 of its width, infundibuliform towards the mouth, the mouth about as wide as the ventricose part, with 2 prominent ribs over the whole length ; mouth nearly round, acute or shortly acuminate towards the lid, not prolongated into a neck ; peristome cylindrical, 1/2 to 1 mm broad, the ribs 1/3 to 1/4 mm apart, often indistinct ; inner margin almost entire ; inner surface of the pitcher with non-overarched glands in its lower 2/3 part, about 200 to 250 on 1 cm2 ; lid orbicular or orbicular-elliptical, rounded or slightly cordate at the base, with many scattered, slightly overarched and rimmed glands ; spur not branched, filiform, up to 3 mm long, inserted close to the lid. Male inflorescence a raceme, the peduncle 7 1/2 to 20 cm long, 2 to 3 mm thick in the lower part, 2 mm in the upper part, the axis 12 to 20 cm long, gradually attenuate ; pedicels without bracts, almost all of them 2-flowered, filiform, 12 to 15 mm long, or shorter near the tip of the raceme. Tepals elliptic, obtuse, 3 to 3 1/2 mm long. Staminal column 2 to 3 mm long, the uniseriate anthers included. Female inflorescence in the main like the male one. Tepals narrower and more acute. Ovary with a pedicel 1/2 to 3/4 mm long. Fruit slender, 10 to 30 mm long, the valves l l/2 to 2 1/2 mm broad, gradually attenuate towards both ends. Seeds filiform, 8 to 15 mm long, the nucleus transversely wrinkled. Indumentum stellate-tomentose on the very young pitchers, the tendrils, the axils, and sometimes also on the midrib of the leaves, the inflorescences more densely hairy

. Fig. 23. Nepenthes tobaica ; a. upper portion of the stem of a female plant, 1/2 x (LÖRZING 8602) ; b. male inflorescence of the same number, 1/2 x ; c. fruiting raceme, 1/2 x (LÖRZING 9889) ; d. male flower, 2 1/2 x (LÖRZING 8602).

towards the flowers, the tepals densely stellate-tomentose at the margin and at the baseinside, the staminal column almost wholly hairy, the ovary densely appressedly haired, the fruit glabrous at length. Colour: stems light-green to dark-brown, leaves green or light-green above, paler beneath, yellowish-brown towards the apex, as is the tendril ; pitchers light-green or yellowish-green with red points or more red, rarely almost wholly red, the ribs of the peristome mostly darker, the inner surface of the pitcher and of the lid light-green with red points or wholly red, rarely entirely green, staminal column light-green, anthers yellow. Colour of herbarium specimens often blackish. (Description after all the specimens under mentioned.)

SUMATRA. Gov. Eastcoast: G. Sibajak, 1300 m, 27 I 1923, LÖRZING 9443, H. B. (0) ; Karo Plateau, on the East-Siosar, 1450-1550 m, 12 XI 1921, LÖRZING 6802, H. B. (m, f), H. L. B. (m.f) ; between Midan and Berastagi, Lau-deboek-deboek, 20 VI 1926, BOEDIJN, H. D. 6408, H. B. (0) ; Berastagi, 1350 m, 12 III 1926, YATES 2013 H. U. C. (m), H. B. (m) ; near Perapat, rocky coast of Lake Toba, 910 m, 11 X 1920, LÖRZING & JOCHEMS, H. D.P. 7612, H. B. (0) ; Haranggoal, near Lake Toba, 1200 m, IV 1927, BEUMÉE A 438, H. B. (0) ; at the way between Perapat and Pematang Siantar, 1000 m, IV 1927, BEUMÉE A 448, H. B. (0) ; Res. Tapiannoeli: on the Sg. Asahan near Lake Toba, 950-1050 m. LÖRZING 9889, H. B. (f) ; Plateau of Habinsaran, E.S.E. of Lake Toba, 1200-1300 m, 11 V 1919, LÖRZING 6573, H. B. (m, f), H. L. B. (f), also on alcohol, type ; about 25 km S.E. of Baligé, 1300 m. 11 XII 1918, RUTGERS & VAN HEURN 1, H. B. (f), H. L. B. (f) ; Benandolok, 1000 m, OUWEHAND 79, H. B. (f) ; TEYSMANN, probably Batak regions, 8 II 1856, H. L. B. 908,155-1106 (f).

N. tobaica has only been found on the plateau north, east and south of Lake Toba. It is most closely related to N. Reinwardtiana and I am not quite certain, whether it is perhaps a form of this species, but up till now no intermediate forms have been discovered.

The elevation on which N. tobaica has been collected varies between 910 and 1550 m. About its habitat LÖRZING says on the label of his number 8602: "In the Leptospermum associations" and on that of his number 6573: "In the scrub of old clearings, sometimes also in the forest of the ravines and in grassy wildernesses, common ; along with Rhodomyrtus and Leptospermum this Nepenthes is one of the most common and characteristic plants." On the label of the specimen, collected by RUTGERS & VAN HEURN, LÖRZING writes: "According to Mr. VAN HEURN this is the commonest plant on vast regions of the plateau of Habinsaran ; it climbs in the Leptospermum trees ; some plants, probably young ones, have only rosettes, others are up to 4 m high." BEUMÉE found this species growing on perpendicular earth-walls.

The rather abundant herbarium material varies little. The two peculiar round spots of the inner surface of the pitcher of N. Reinwardtiana seem to be absent in N. tobaica.

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