Amorphophallus tinekeae: The Shade-Dwelling Giant Aroid of Borneo’s Deep Forests
Hidden beneath the canopy of deep-shaded forest slopes in Borneo, Amorphophallus tinekeae Hett. & A.Vogel represents one of the more recently described aroids in the Indonesian and Malaysian flora. Hetterscheid and Vogel formally described it in 2001 in the journal Blumea. Its distribution spans East Malaysia (Sabah) and possibly North Kalimantan in Indonesia. A. tinekeae belongs to an exclusively Bornean species group and produces a strikingly elegant inflorescence: a broadly campanulate spathe that closes after anthesis and a long, slender, dark-maroon narrowly conic appendix. For collectors and botanists working in Bornean rainforest aroid diversity, this species occupies a distinctive and scientifically interesting position within its genus.
Taxonomic Identity of Amorphophallus tinekeae
Amorphophallus tinekeae belongs to the family Araceae. Hetterscheid & A.Vogel described it in Blumea 46 (2) (2001): 276. No synonyms are currently recognized for this species.
Morphological Description
Tuber and Leaf
The tuber of Amorphophallus tinekeae is subglobose, approximately 20 cm in diameter and 13 cm tall. It is off-white in color, with several raised areas on its surface. The petiole reaches up to 160 cm in length and 5 cm in diameter. Near the base it is slightly rugulose; otherwise the surface is smooth. The background color is off-white, nearly entirely covered by small, transverse, very dark blackish-green crack-like spots. Larger, elongate-elliptic, dirty whitish spots are also scattered across the surface, with or without a dirty olive-brown center.
The lamina reaches up to 160 cm in diameter. Its rachises are winged almost to the base. Leaflets are elliptic to elongate-elliptic, acuminate, 7–26 cm long and 3–9 cm in diameter. The upper surface is slightly leathery and glossy mid-green.
Inflorescence and Peduncle
The inflorescence of Amorphophallus tinekeae is short to medium-peduncled, and never distinctly longer than the spathe. The peduncle measures 13–36 cm long and 1–2 cm in diameter. Its surface is smooth and matches the petiole in coloration.
Spathe
The spathe is transversely oval, 18–35 cm long and 16–32 cm in diameter, and leathery in texture. The limb is oblique. After anthesis it actively curves forward, closing the spathe opening. The outer base surface has a lower half that is bright green with thin maroonish veins and a very few scattered small white spots. Upward, it is flushed with greyish to blackish maroon. The veins become prominently maroon to blackish-purple toward the top. The inner base surface is deep maroon. The central part is whitish-greenish. The upper inner portion is flushed with greyish maroon. The base within is densely verruculate with several lengthwise grooves. The outer limb surface is largely green with brownish-purple venation, flushed upward with dirty purplish-brown. The inner limb surface is pale green, with the margin flushed with dirty purplish-brown and incurved.
Spadix and Floral Zones
The spadix of Amorphophallus tinekeae is sessile and longer than the spathe, measuring 21–58 cm in total. The female zone is slightly conic, 2.5–7 cm long and 1.8–3 cm in diameter. Its flowers are congested or slightly distant. The male zone is slightly obconic, 3–6.5 cm long and 1.3–2.3 cm in diameter. Its flowers are congested.
The appendix is elongate and narrowly conic, 15.5–45 cm long and 1.3–3 cm in diameter at one-third from the base. It gradually tapers toward the acute top. The surface is dark maroon and slightly rugulose. The base carries a few narrow grooves. This long, slender, dark-maroon appendix is one of the most visually striking features of the species.
Female Flowers
Each ovary is depressed-globose, 3 mm in diameter and 2 mm tall. It is bilocular and dark maroon. The style is 4 mm long and 1 mm in diameter, and maroon. The stigma is laterally placed and highly asymmetrical. It is ovate in upper view, with a long axis of approximately 3 mm and a short axis of 2 mm, approximately 1 mm thick. It is one-lobed, with the lobe apical on the style and conic in shape. Below the lobe sits a shallow, slightly curved depression. The stigma surface is echinulate and dirty yellowish-brown.
Male Flowers
Each male flower carries 4–5 stamens. Stamens reach approximately 2 mm in length and 1.5–2 mm in diameter. Filaments are 1.2 mm long and half-connate. Anthers are 0.8 mm long, truncated, and off-white. Connectives are off-white or brownish. Pollen is psilate.
Fruit
The infructescence fruiting part reaches approximately 20 cm long and 1.5 cm in diameter. Berries are globose to depressed-globose, 9–12 mm in diameter and 8–9 mm long, and orange-red. Seeds are subglobose to unilaterally depressed, 7–8 mm in diameter, with a very deep short groove or shallow depression. The seed coat is minutely rugulose and ivory-white.
Distribution of Amorphophallus tinekeae
Amorphophallus tinekeae grows in East Malaysia (Sabah) and possibly in North Kalimantan, Indonesia. The Kalimantan record currently carries some uncertainty, hence the qualifier in the source literature. Further field collections from Indonesian Borneo would help confirm or clarify the species’ presence there.
For verified occurrence data and georeferenced records, refer to GBIF – Amorphophallus tinekeae and the Plants of the World Online (POWO) – Kew.
Habitat
This species grows on slopes in deep-shaded forest. Its strict preference for shaded, closed-canopy conditions distinguishes it from many disturbed-habitat generalists in the genus. Consequently, continued integrity of primary and near-primary forest in Borneo is essential for the long-term persistence of A. tinekeae populations.
Taxonomic Notes
Amorphophallus tinekeae belongs to an exclusively Bornean species group that also includes A. borneensis, A. lambii, and A. hewittii. Within this group, only A. borneensis has so far been confirmed from Kalimantan. The remaining members grow primarily in Sabah and Sarawak.
Among its closest relatives, A. tinekeae differs most clearly from A. borneensis in two ways. First, A. tinekeae carries a notably short peduncle — never distinctly longer than the spathe. Second, its spathe is a much more widely opening campanulate form compared to A. borneensis. These two characters together make field identification straightforward when flowering material is available.
Photo Reference
The following photographs illustrate Amorphophallus tinekeae (Photos: Wilbert Hetterscheid):
References
- Hetterscheid, W.L.A. & Vogel, A. (2001). Amorphophallus tinekeae Hett. & A.Vogel. In: Blumea 46 (2): 276.
- Kew Science. Amorphophallus tinekeae Hett. & A.Vogel – Plants of the World Online. Available at: https://powo.science.kew.org/
- GBIF Secretariat. Amorphophallus tinekeae occurrence data. Global Biodiversity Information Facility. Available at: https://www.gbif.org/
-
