Sumatra sugar palm seeds (Arenga obtusifolia) 
Quantity : 05 Seeds


Synonyms :
Gomutus obtusifolius Blume (1843); Saguerus langbak Blume (1843).


Arenga obtusifolia, commonly known as the Sumatra sugar palm, is an impressive species native to the humid forests of Java, Peninsular Malaysia, Sumatra, and Thailand. In these regions, it is often found thriving in the undergrowth of the forest, sometimes even becoming the dominant species at altitudes up to 700 meters. The plant is renowned for its distinctive, robust characteristics and is particularly valued in the local culture for various uses.

The genus name "Arenga" is derived from the Malay word areng, referring to Arenga pinnata, a close relative. The specific name obtusifolia combines the Latin words obtusus (blunt) and folium (leaf), alluding to the plant's distinctive blunt leaves.

Physical Description and Growth Habit

Arenga obtusifolia is a cespitose, unarmed species that grows through the expansion of stolons (up to 2 meters long). The palm typically reaches heights of 8 to 15 meters, with its base measuring around 30 cm in diameter. A unique feature of this species is that it is not monocarpic, meaning it does not die after blooming, unlike many other palms in the genus. Instead, the blooming occurs from the bottom of the plant upwards (acropetal), contrary to the more common basipetal blooming pattern. The palm is also monoecious, bearing both male and female flowers on the same inflorescence. However, during its development, all the flowers of one sex may be eliminated, making it behave as dioecious for reproductive purposes.

Leaves and Foliar Characteristics

The leaves of Arenga obtusifolia are large and striking, measuring up to 6 meters in length on a robust petiole that ranges from 40 to 90 cm. These pinnate leaves are slightly ascending and feature 60-100 lanceolate pinnules. The pinnules themselves are irregularly toothed at the apex, measuring between 0.7 and 1.5 meters long and 6 to 8 cm wide. Their coloration is dark green above, with a silvery grey underside, and the texture is coriaceous. The base of the leaf, which is 0.6 to 1 meter long and grey in color, wraps around the stem minimally, with the margins forming a network of blackish fibers that persist for an extended period. In older plants, these fibers become needle-like and can extend up to 1 meter in length. The trunk of the palm remains smooth and greyish in older plants, marked by rings that indicate the fallen leaves, spaced about 16-20 cm apart.

Flowers and Fruit

The inflorescences of Arenga obtusifolia emerge between the leaves (interfoliar), with branching structures that reach up to 1 meter in length. The fruit is ovoid with a flattened apex, turning a greenish-yellow when ripe. These fruits measure around 4.5 cm long and 3 cm in diameter, containing 1-3 blackish seeds. However, the pulp is highly irritant due to the presence of calcium oxalate crystals, requiring careful handling—preferably with gloves.

Reproduction and Propagation

Arenga obtusifolia can be propagated through division or by seed. When grown from seed, the plant requires deep containers to accommodate the developing hypocotyl, which extends deep into the soil. Germination occurs at temperatures between 26-28°C and typically takes over a month to complete.

Cultivation and Uses

While Arenga obtusifolia is undeniably an ornamental species, it is important to control its growth due to its spreading nature via stolons. Without proper management, it can occupy large areas, especially in parks or large gardens in tropical or humid subtropical climates. It is not frost-tolerant, and temperatures around 0°C can cause significant damage to its foliage, even if for short periods. The palm thrives best in full sun and well-drained, constantly humid soil.

The fruits of Arenga obtusifolia are sometimes used as feed for pigs, and the leaves are employed for thatching, making baskets, and creating makeshift shelters. In some regions of Java, however, it has become invasive, choking existing vegetation and posing a threat to native species, including the endangered Javan rhinoceros (Rhinoceros sondaicus). This has led to the establishment of response plans by local authorities to manage its spread and support the regrowth of native vegetation.

Ecological and Conservation Impact

While Arenga obtusifolia has clear economic and practical value, its invasive nature is a significant concern, particularly in areas where it disrupts local ecosystems. Its rapid spread, aided by stolon growth, has contributed to the decline of natural habitats, and it has been noted to threaten the survival of the Javan rhinoceros. Efforts are underway to mitigate the impact of this species in affected areas, such as the Ujung Kulon National Park, where the rhinoceros population is critically low.