AMORPHOPHALLUS JULAIHII
PROTOLOGUE: Amorphophallus julaihii Ipor, Tawan & P.C.Boyce, published in Gard. Bull. Singapore 56: 156 (2004).
Amorphophallus julaihii Ipor, Tawan et P.C. Boyce sp. nov. Ab omnibus speciebus in habitu calcicola lithophytica Borneensibus borealis spatha parva in toto atropurpureis differt. Typus. Sarawak, Miri Division, Mulu National Park, forest on limestone, C.S. Tawan & I.B. Ipor CST 2527, 14 April 2004 (Holotypus: HUMS (Herbarium Universiti Malaysia Sarawak) inflorescence and tubers in spirit; vegetative parts (petiole with leaflets, seedlings) - herbarium specimens.)
DISTRIBUTION: Borneo (Sarawak): Borneo.
DISTRIBUTION NOTE: Sarawak: Miri Division, Mulu National Park.
SPECIES DESCRIPTION:
Small to medium-sized herb, 50–100 cm tall. Tuber depressed sub-cylindrical to globose, with irregular raised areas, up to 5.8 cm diam., 6.0 cm high, surface dull brown greyish, inner part fleshy, whitish. Adventitious root scars present on top portion of tuber at flowering stage, new roots developing during vegetative stage. Petiole up to 44 cm long, c. 19 mm diameter at base, turgid, cylindrical, smooth, bright green, enveloped basally by dried decaying brownish cataphylls; lamina highly dissected, rachises naked, narrowly channelled, yellowish green; leaflets elliptic-lanceolate, 11.0–13.0 x 4.0–4.4 cm, some petiolulate, petiolule 1.5–3.0 cm long, slightly channelled adaxially, ultimate leaflet sessile, leaflets asymmetrical, apex apiculate 1.5–2.0 cm long; base unequal; margin slightly wavy and sparsely fine-toothed; adaxial surface bright green, thin slightly leathery, abaxial surface pale green; 6–16 pairs of secondary veins with intermediate veins per leaflet, these adaxially channelled and adaxially raised; venation forming distinct submarginal veins; tertiary veins reticulate; lamina texture leathery when fresh, chartaceous when dry.
INFLORESCENCE:
Inflorescence solitary, flowering without foliage leaves; peduncle cylindrical, up to 17.5 cm long, 8–9 mm diam. at base, yellowish to creamy. Cataphylls 6; first 1–4 ovate to linear, 3–13 cm x 1.5–2.0 cm, brownish to dark brown, thin, soon withering and decaying; the next 5–6 linear-oblong, 15–21 x 2.4–3.5 cm, light purplish to whitish and slightly purplish stained. Spathe elongate-oblong, limb erect at anthesis, later recurved and twisted towards the base, up to 12 cm long, width at base 4.0 cm, at middle 4.0 cm, at apex 4.5 cm, lower spathe strongly convolute and forming a short tube 3.5–4.0 cm long; inner surface of upper spathe limb ribbed with distinct venation, purplish, lower part rough and verrucose, deep purple; outer surface of upper spathe limb with distinct longitudinal venation, margin thinly undulate, apex dentate; upper part of spathe limb rich purple-scarlet, middle part and margins darker. Spadix exceeding spathe, 18.5–19.0 cm, short stipe, 1.0–1.5 cm long. Appendix up to 14 cm long, cylindrical, spongy, purplish, 9–9.2 mm diam. at base; 7.5 mm diam. at middle, 2 mm diam. at apex, surface verrucose with longitudinal lines, appendix producing an unpleasant odour similar to that of rotten fish. Flowers unisexual; male zone cylindrical, up to 3 cm long, 9 mm diam. at middle, whitish to creamy; stamens connate and short, c. 1 mm long, c. 0.5 mm broad across, fused with adjacent stamens, filaments c. 5 mm, truncate, pores apical, rounded or variously elongate. yellowish or creamy, pollen brownish. Female zone cylindrical, separated by irregular zone of sterile stamens from the male zone, 1.5–2 cm long, 10 mm diameter; pistils in irregularly rows, rather lax, sometimes almost in V-shaped rows; ovaries ovoid-subglobose, 2.5–3.0 mm in long, 1.8–2.0 mm broad at base, dark purple, unilocular rarely bilocular; stigma sessile, two to three lobed or sometimes irregularly lobed, Infructescence with up to 35 berries, pedunculate up to 22 cm long, 6 mm diam. at base, 9 mm diam. at apex, with blackish-dark brown V-shaped scar from the marcescent spathe, basally with remains of the cataphylls. Berries when ripe deep orange, ellipsoid 15–16 mm x 8–10 mm, apex rounded, with blackish stigma remnants, one seeded. Seeds ellipsoid, 12–14 mm x 7–8.2 mm wide, testa smooth, thin, yellowish green, seed copiously starchy, embryo small.
ECOLOGY:
Found in limestone forest, growing in shady areas, in humus-filled fissures and holes in limestone. Flowering recorded in April; altitude: 40 m
ETYMOLOGY:
Named in honor of Julaihi Abdullah, Deputy Research Manager of the Sarawak Forestry Corporation and formerly Botanist of the Sarawak Forest Department, Kuching, who first showed the first two authors this species in Mulu National Park, Sarawak. The Latinized epithet julaihii means “of Julaihi.”
NOTES:
1. Amorphophallus julaihii is most similar to Amorphophallus angulatus, Amorphophallus brachyphyllus and Amorphophallus eburneus, (all Sarawak) and Amorphophallus costatus (Kalimantan). From Amorphophallus angulatus (with which Amorphophallus julaihii shares a purple spathe), it differs by the spadix appendix exceeding the spathe and by the smaller, not diamond-shaped male flowers. From Amorphophallus eburneus and Amorphophallus brachyphyllus (also both restricted to limestone), Amorphophallus julaihii is immediately separable by the purple ribbed spathe. The resemblance of Amorphophallus julaihii to Amorphophallus costatus is in having an erect elongate triangular spathe with the base strongly convolute forming a narrow tube. In both species, the spadix exceeds the spathe but in Amorphophallus julaihii the spadix is shortly stipitate while it is sessile in Amorphophallus costatus; the male zones in both species are similar - cylindrical, flowers slightly distinct, irregularly arranged or in longitudinal oblique, interrupted rows. The matt-purple spathe of Amorphophallus julaihii readily separates it from Amorphophallus costatus in which the spathe interior is glossy maroon. To date Amorphophallus costatus is recorded only from southern Kalimantan.
STORY:
STORY TITLE: Pollination watch on the Deer Cave karst
In March and again in August 2017, a Universiti Malaysia Sarawak team returned to the karst limestone along the trail to Deer Cave in Mulu National Park — the same formation where Amorphophallus julaihii had been discovered — to watch a population of roughly one hundred plants through flowering. It was the first time the floral biology of any species in its clade had been studied in the wild.
Flowering falls between August and October, and in this clade anthesis opens in the morning — the opposite schedule from afternoon-blooming relatives such as Amorphophallus hewittii, whose flowering peaks overlap in the same forests. The appendix of Amorphophallus julaihii emits an odour of rotten fish, and the guest list it draws is short: rove beetles (Staphylinidae) arrive during the pistillate phase, joined during the staminate phase by carrion beetles (Silphidae) and thrips. Compared with the crowds of scarabs, bees, flies and even cockroaches recorded on Amorphophallus hewittii, this is an exclusive establishment — a pattern the authors tie to odour chemistry, with the fishy trimethylamine-dominant species attracting far fewer visitor types than their carrion-scented relatives.
The narrow clientele seems to serve the plant well. Fruit set averaged 75.6% ± 11.2% — well above the sympatric limestone specialist Amorphophallus eburneus (54.1% ± 14.4%) and close behind the far more generalist Amorphophallus hewittii (82.7%).
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus julaihii Ipor, Tawan & P.C.Boyce
2. Gard. Bull. Singapore 56: 156 (2004) — protologue.
3. Alan Galloway — Amorphophallus julaihii, alangallowaybotanicals.com.
Additional photos by Juan Jimenez, Justin Scholten, Pio Swiat, Yueranic Oliver Ingold Chien Lee