AMORPHOPHALLUS PALAWANENSIS
PROTOLOGUE: Amorphophallus palawanensis Bogner & Hett., published in Blumea 36: 473 (1992).
Amorphophallus palawanensis Bogner & Hetterscheid, spec. nov. Herba parva, tuber depresso-globosum, folia gracilia, segmentis elliptico-lanceolatis, acutis vel acuminatis. Spatha utrinque purpurea, marginibus sub anthesi reflexis, basi convoluta, intus laevis, leviter constricta. Spadix spatha brevior. Flores feminei pauci, plerumque verticillo solitario dispositi, stigma parvum in stylo non angustiore positum. Flores masculini laxe dispositi, 2 vel 3(4)-staminati. Typus: Bogner 2109 (M, holo), Philippines, Palawan (West), Underground River, Piedras Point, Cliffs Head, 0-40 m alt., growing in humus deposits on limestone; living tubers originally collected by O. Riegler, cultivated plants flowered in Munich Botanic Garden, 1991. Paratype: Hetterscheid H.AM.124 (L), same origin as holotype.
DISTRIBUTION: Philippines: Philippines.
DISTRIBUTION NOTE: Philippines: Palawan - the Underground River at Piedras Point, Cliffs Head, on the west of the island; known only from the type collection.².
SPECIES DESCRIPTION:
Tuber globose or depressed-globose with semi-globose vegetative outgrowths and a deep central depression, 4-6 cm in diam. and c. 5 cm deep, light brown, roots strong, 2-2.5 mm thick. Petiole 30-50 cm long, diam. 0.9-1.8 cm at base, 0.4-0.9 cm above, pale green, smooth. Leaf-blade divided into three main parts, 35-100 cm in diam., leaflets more or less elliptic-lanceolate, decurrent, often oblique, the proximal ones smaller than the terminal ones, 5-21.5 cm long, 1.0-3.9 cm wide, acute to acuminate with an apex c. 2 cm long, upper side green; venation reticulate, main vein strong, 5-10 primary lateral veins on each side, two collecting veins, the outer one very near the margin at c. 0.5 mm, the inner one c. 3 mm from the margin.⁴
INFLORESCENCE:
Inflorescence with three membranaceous cataphylls, these withering soon and turning brown, 1.5-7.0 cm long, rounded at the top and apiculate. Peduncle c. 27 cm long, 0.5 cm in diam. at the base to 0.4 cm above, pale green. Spathe c. 8 cm long, purple on both sides, the veins and the inner basal surface slightly darker, lower part convolute for c. 3 cm, upwards slightly constricted, margins somewhat reflexed, inside smooth also at the base, limb apex acute. Spadix c. 4.5 cm long; female zone more or less consisting of only one whorl of pistils; male part cylindric, c. 2 cm long and 0.5 cm in diam., cream; appendix conical-acute, constricted near the base and more or less stipitate, pale purple, c. 2.3 cm long. Pistils bright green, c. 3 mm high; ovary depressed-globose, c. 2.5-3.0 mm in diam., c. 1.5 mm high, unilocular with one ovule, the locule c. 0.8 mm in diam.; ovule c. 0.5 mm long, funicle very short; style c. 1 mm long, c. 0.7 mm thick in the middle, narrowing towards the stigma; stigma discoid, flat, not prominent, not broader than the style, c. 0.5 mm diam., whitish. Male flowers consisting of 2 or 3(4) stamens, these always distinctly grouped and leaving the reddish axis of the spadix partly visible; stamens sessile, 1.0-1.2 mm high, apex rounded, subrectangular in horizontal section, 1.8-2.5 x 0.9-1.1 mm; thecae opening with a nearly rounded pore. Pollen grains ellipsoid, inaperturate, 45-55 x 30-38 µm, exine striate, the striae 8-18 µm long, variously anastomosing.²
ECOLOGY:
Found growing in humus deposits on limestone; altitude: 0-40 m²
PROPAGATION:
Our only attempt with this species in mid-October yielded no success.
ETYMOLOGY:
From Palawan and the Latin geographical suffix-ensis, “from” or “of,” literally “from Palawan.” The epithet directly reflects the species’ provenance on Palawan Island in the western Philippines. Amorphophallus pendulus
NOTES:
1. Diagnosis: a small plant with a depressed-globose tuber and slender leaves whose segments are elliptic-lanceolate and acute to acuminate; the spathe is purple on both faces with margins reflexed at anthesis, convolute at the base, smooth within and slightly constricted; the spadix is shorter than the spathe; the female flowers are few and mostly set in a single whorl, with a small stigma no broader than the style; and the male flowers are laxly arranged with 2 or 3, rarely 4, stamens.²
2. The species is easily recognised by a combination of characters: its small dimensions, a spathe brownish-purple on both sides, very few female flowers, a small stigma, and laxly disposed male flowers.²
3. The chromosome number was counted from the type material as 2n = 26.²
4. The female zone amounts to little more than a single ring of pistils, and because the male flowers sit in distinct groups the reddish axis of the spadix stays partly visible between them.²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus palawanensis Bogner & Hett.
2. Blumea 36: 473 (1992) — protologue.
3. Alan Galloway — Amorphophallus palawanensis, alangallowaybotanicals.com.
4. Aroideana 19 (1996):P7 - 131
5. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden