AMORPHOPHALLUS SAGITTARIUS

PROTOLOGUE: Amorphophallus sagittarius Steenis, published in Acta Botanica Neerlandica 2(3): 302 (1953).

44. A new Amorphophallus from Java (Arac.). Fig. 3. Amorphophallus Sagittarius n. sp. - Folia in specimine unico viso haud bulbillifera, petiolo ± 34 cm longo sustenta; segmentis primariis lateralibus petiolulis 5-7 cm longis suffultis, semel furcatis; foliola totaliter 14, oblique oblonga, basi haud alatiforme decurrentia, manifeste caudato-acuminata, nervo marginali subundulato, 6-17 cm longa, 2½-6 cm lata. Tuber subglobosum subdepressum, 4-5 cm latum, 3-4 cm altum. Pedunculus ± 12 cm longus, ± 8 mm crassus, basi munitus squamis plurimis vaginiformibus appressis brunneis, quarum intima ceteris longior pedunculum subaequans. Spatha spadici subaequilonga, ovata, obtusa, expansa ca. 13 cm longa, ± 10 cm lata, extus basin versus pallida, juxta marginem superiorem intense purpureo-olivacea, maculis pallide viridibus conspersa. Spadicis pars ♀ cylindrica ca. 11 cm longa, 8 mm crassa; ovaria intervallis sejuncta, subdepresso-globosa, viridia, 1-ovulata; stigma sessile, capitatum integrum, ± 1½ mm diam.; spadicis pars ♂ subcylindrica, superne paullulo incrassata, ± 3½ cm longa, 8 mm lata; antheris confertis pallide aurantiaca, ± 2 mm longa. Appendix sterilis lanceolata, cremicolor, minute tuberculata, ± 7 cm longa, medio bene 1 cm lata. Typus: L. van der Pijl 899a, ins. Java occid. pr. Tjisadea, 8/11-1941 (Bo).

DISTRIBUTION: W. Jawa: Java.

DISTRIBUTION NOTE: Java: endemic to the island, with gatherings from West Java at Tjisadea near Bogor and at Situ Gunung.⁶.

SPECIES DESCRIPTION:

Tuber subglobose, yellowish brown, 4-5 cm high and about 6 cm across, weighing up to 120 g. Leaf solitary; petiole smooth, slender, turgid, 30-40 cm long and about 1 cm across at the base, grading from mid-green at the base to dark green with bright green spots ringed in whitish and blackish green. Lamina 60-80 cm across, the rachises not winged; leaflets elliptic-lanceolate, acuminate, 6-23 cm long and 2.5-9 cm wide, moderately glossy green above and greyish green beneath, the primary veins sunken above and slightly raised beneath.⁶

INFLORESCENCE:

Inflorescence solitary, subtended by about 5 membranous cataphylls; peduncle 12-21 cm long and 0.5-0.8 cm across, coloured as the petiole. Spathe erect, 13-19 cm long and 9-10 cm across; the lower spathe convolute and narrowly oblong, outside pale brown or light yellow with large and small pale green or white spots that often partly run together, inside whitish-green or off-white with many small warts at the base; limb erect and somewhat twisted near the top, ovate or ovate-lanceolate with an obtuse or acute tip, glossy maroon on both surfaces. Spadix sessile, shorter than or equalling the spathe, 13-15.5 cm long; female zone cylindric, 1.3-2 cm long and 0.8-1 cm across, the pistils closely packed or slightly apart; ovary globose to subglobose, 0.2-0.4 cm across and 0.15-0.25 cm long, pale green and sometimes maroon near the style, one-chambered with a single ovule on a basal placenta; style to 0.5 mm long and about 0.1 cm across, maroon or green; stigma 0.1-0.15 cm across, variable, often set obliquely on the style and strongly one-sided, flat and disc-shaped or with a variously folded margin, often 3-lobed. No sterile zone. Male zone subcylindric and slightly obconic, about 4 cm long and 0.8-1.3 cm across; stamens subtruncate, 0.2 cm long; filaments 0.1 cm long, connate at the base; anthers polygonal in cross section, 0.1 cm long and 0.1-0.2 cm across, pale yellow or pale purplish-violet, the thecae opening by apical pores. Appendix elongate and acute, 7-9.5 cm long and 1-1.8 cm across near the base, off-white to pale yellow, the surface minutely to distinctly warted. The fruit has never been seen.⁶

ECOLOGY:

Found in secondary forest on slopes. The type came from about 1000 m.⁶

ETYMOLOGY:

From Latin sagittarius, “archer” or “arrow-bearing,” derived from sagitta, “arrow.” The exact morphological allusion intended by the original author is unclear from the available description, so the epithet is best interpreted cautiously rather than assigned to a specific structure without the protologue.

NOTES:

1. The species was described by van Steenis in 1953 from material gathered in West Java by van der Pijl in November 1941, and it is endemic to Java.⁶

2. It is separated from Amorphophallus variabilis by two things: a short peduncle, up to 21 cm against up to 120 cm, and a spadix about equalling the spathe rather than roughly twice its length.⁶

3. Each ovary has a single chamber and a single ovule.⁶

4. The stigma is markedly irregular - often set on the style at an angle and strongly one-sided, flat and disc-like or with a folded margin, and frequently three-lobed.⁶

5. The fruit has never been described.⁶

6. The measurements in the original description were taken from the living plant, not from dried material.²

7. van Steenis could not place it in Backer's key to the Javan species. Its one-ovuled ovary put it nearest Amorphophallus spectabilis, which he had collected himself several times and which differs plainly in size, in the size, shape and colour of the spathe, and in the proportions of the three parts of the spadix. He judged it closer to two Sumatran species, Amorphophallus cobra and Amorphophallus obovoideus - both of which have a spathe exceeding the spadix and a differently shaped appendix - and remarked in passing that those two seemed to him to be one species.²

8. He considered and rejected the possibility that it was the long-lost Amorphophallus giganteus of Blume, whose figure shows an inflorescence of similar habit and which had never been refound in Java. Blume's plate shows two-chambered ovaries, and this species has one chamber and one ovule. Backer had in any case supposed Blume's description to combine the leaves of one species with the inflorescence of another.²

9. ⚠ The type number is printed two ways. The protologue gives L. van der Pijl 899a; the 2009 Javanese revision gives 889a. Collector, locality, date and herbarium agree in both.²

10. The plants van der Pijl grew at Bandung before the war were lost. He reported that in cultivation there they developed glossy brown-purple spathes - a colour shift he had also seen in cultivated Arisaema.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus sagittarius Steenis

2. Acta Botanica Neerlandica 2(3): 302 (1953) — protologue.

3. Alan Galloway — Amorphophallus sagittarius, alangallowaybotanicals.com.

4. Aroideana 19 (1996):P7 - 131

5. iNaturalist: Amorphophallus sagittarius

6. Amorphophallus Blume ex Decaisne (Araceae - Thomsonieae) in Java. Reinwardtia 13(1): 1-12 (2009)