Amorphophallus variabilis: Java’s Most Variable and Widespread Aroid
Among the aroids of Java, Amorphophallus variabilis Blume stands out as the most frequently encountered and morphologically versatile species on the island. Blume formally described it in 1837 in the Rumphia. Its distribution spans Java, Madura, the Kangean Islands, Bali, and Lombok. True to its name, this species exhibits extraordinary plasticity in vegetative and floral characters — from the color and pattern of its petioles to the size and shape of its inflorescence. Despite this variability, two consistent characters separate it from other long-peduncled, long-spadix Javan aroids: its relatively smaller dimensions and its spathe, which is always pale green in background color and never shows purplish tones. For botanists working in Javan forest flora, A. variabilis is an indispensable and endlessly fascinating species.
Taxonomic Identity of Amorphophallus variabilis
Amorphophallus variabilis belongs to the family Araceae. Blume described it in Rumphia 1 (1837): 146. Several synonyms reflect its long taxonomic history:
- Amorphophallus variabilis var. cuspidifoliolatus Engl. & Gehrm.
- Amorphophallus variabilis var. immaculatus Hassk.
- Amorphophallus zeylanicus Engl.
- Arum caeruleopunctatum Zipp. ex Kunth
- Arum stercorarium Zipp. ex Kunth
- Brachyspatha variabilis (Blume) Schott
Morphological Description
Tuber and Leaf
The tuber of Amorphophallus variabilis is depressed-globose, up to approximately 15 cm in diameter and 8 cm tall, and white in color. It weighs up to approximately 1,500 g. The tuber produces numerous annual offsets. These offsets are shortly spindle-shaped and 1–1.5 cm long. The plant bears one leaf, occasionally two. The petiole extends up to 120 cm long and approximately 3.5 cm in diameter at the base. Its surface is smooth or slightly rugose at the base.
Petiole coloration is highly variable. Some plants (var. immaculatus) are entirely green. Others display a green, olive-green, or dark brown background variegated with large and small, confluent and free, oval, rounded, or elongate spots of dark green, white, or greyish-green. The lamina reaches up to 125 cm in diameter, with narrowly winged rachises except at their basal parts. Leaflets are elliptic to elongate-elliptic, acuminate to long-acuminate, 4–34 cm long and 2–12 cm wide. Their upper surface is moderately glossy mid-green.
Inflorescence and Peduncle
The inflorescence of Amorphophallus variabilis is solitary and long-peduncled. The peduncle matches the petiole in appearance and measures 8–120 cm long and 0.4–3 cm in diameter at the base.
Spathe
The spathe is erect and elongate-triangular, acute, 6–23 cm long and 5–20 cm in diameter. A slight constriction separates the base from the limb. The limb narrows suddenly near the base. The margin of the limb is strongly reflexed. The outer limb surface is entirely green or dirty green with scattered small black dots. Toward the margin, the veins are suffused with brown and appear pale greenish. The inner base is maroon, reddish-brown, orange, or yellowish, with the remainder creamy white. The inner limb surface is creamy white, pale green, or pale reddish-brown. The interior base surface carries numerous small, laterally flattened warts and oozes a clear fluid during anthesis.
Spadix and Floral Zones
The spadix of Amorphophallus variabilis is sessile and usually much longer than the spathe, measuring 9–58 cm in total. The female zone is cylindric to slightly conic, 0.7–4 cm long and 1–2.2 cm in diameter at the base. Its flowers are congested. The male zone is cylindric, slightly fusiform, or slightly obconic, 2–6 cm long and 0.6–1.8 cm in diameter. Its flowers are also congested.
The appendix is elongate-conic, acute, terete or slightly laterally compressed, measuring 6–48 cm long and 0.5–3 cm in diameter. Its color is creamy white, greyish-brown, or pale brown. The appendix emits a powerful gaseous smell. Its surface is verruculose, with several shallow and elongate grooves that are deepest and most numerous near the appendix base.
Female Flowers
Each ovary is depressed and subcircular or diamond-shaped in cross-section, 3–4 mm in diameter and 2–2.5 mm tall. It is 2– (–3)-locular and bright green. The style is 0.5–2.5 mm long and 0.5–0.8 mm in diameter, and pale green or purple. The branches of the upper part of the style often extend laterally alongside the stigma, sometimes protruding beyond its surface. The stigma is oval, elliptic, triangular, or subquadrangular in cross-section, 1–2.5 mm in diameter and 0.8–1.3 mm tall. It is yellow, dirty yellow, or pale brownish, and shallowly to strongly bilobate, trilobate, or quadrilobate. The surface is minutely scabrate, with hemispheric or conic lobes.
Male Flowers
Each male flower carries 3–4 stamens. Stamens are 2–2.3 mm long. Filaments are approximately 0.2 mm long and basally connate. Anthers are rectangular in cross-section, 1.8–2.1 mm long and 1.5–2 × 0.5–0.8 mm in diameter, subtruncate and off-white. Pores are apical and elongate.
Fruit and Seed
The infructescence is cylindric, 8–16 cm long and approximately 3 cm in diameter. Berries are at first green, later turning orange-red, and hold one to two (–three) seeds. Seeds are subglobose, obovoid, or elliptic, and flattened on one side.
Distribution of Amorphophallus variabilis
Amorphophallus variabilis occurs across Java, Madura, the Kangean Islands, Bali, and Lombok, Indonesia. This makes it one of the most broadly distributed aroid species endemic to the Lesser Sunda and Greater Sunda island chain.
For verified occurrence data and georeferenced records, refer to GBIF – Amorphophallus variabilis and the Plants of the World Online (POWO) – Kew.
Habitat
This species grows in teak forests, Altingia (Rasamala) forests, disturbed forests, village gardens, and plantations, from sea level to 700 m altitude. Its tolerance for disturbed habitats and human-modified landscapes helps explain its status as the most common aroid on Java.
Taxonomic Notes
Amorphophallus variabilis is a common species in Java. It exhibits considerable plasticity in its characters — particularly in petiole and peduncle coloration, and in inflorescence size and shape. Nevertheless, researchers distinguish it reliably from other long-peduncled, long-spadix Javan species by two consistent characters. First, its overall dimensions are smaller. Second, its spathe always carries a pale green background color and never shows any purplish tones. These two features together allow confident identification even in the presence of variation in other characters.
Furthermore, local names reflect the awareness of variability within the species. In Javanese, cumpleng and acung (Sundanese) or lorkong (Madurese) are common names. Growers sometimes cultivate it for its edible tuber and young shoots, which local communities eat after appropriate preparation.
Photo Reference
The following photographs illustrate Amorphophallus variabilis (Photos: Yuzammi):
References
- Blume, C.L. (1837). Amorphophallus variabilis Blume. In: Rumphia 1: 146.
- Yuzammi (2009). The genus Amorphophallus Blume ex Decaisne (Araceae – Thomsonieae) in Java. Reinwardtia 13: 1–12.
- Kew Science. Amorphophallus variabilis Blume – Plants of the World Online. Available at: https://powo.science.kew.org/
- GBIF Secretariat. Amorphophallus variabilis occurrence data. Global Biodiversity Information Facility. Available at: https://www.gbif.org/species/2871580
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