Arenga microcarpa

Arenga microcarpa

The aren sagu or arrack palm, small-fruited areng palm, toddy palm, wild sagu (Arenga microcarpa Becc., 1889) is a palm belonging to the Arecaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Magnoliophyta division,
Class Liliopsida,
Arecales Order,
Arecaceae family,
Genus Arenga,
Species A. microcarpa.
The terms are synonyms:
– Arenga gracilicaulis F.M.Bailey;
– Arenga microcarpa var. keyensis Becc.;
– Didymosperma humile Lauterb. & K.Schum.;
– Didymosperma microcarpum (Becc.) Warb.;
– Didymosperma microcarpum (Becc.) Warb. ex K.Schum. & Lauterb.;
– Didymosperma novoguineense Warb.;
– Didymosperma novoguineense Warb. ex K.Schum. & Lauterb..

Etymology –
The term Arenga comes from aren(g), Malay vernacular name of a palm belonging to this genus and referring to the Arenga pinnata.
The specific microcarpa epithet comes from the Greek μικρός small micrós and from καρπός carpόs fruit: with small fruits.

Geographic Distribution and Habitat –
Arenga microcarpa is a palm endemic to Maluku, New Guinea, in the open lowland areas near the waterways of Irian Jaya and Northern Territory of Australia.
Its habitat is that of the primary rain forest, frequently present in the humid forests at low altitudes along the watercourses and only rarely in areas of secondary growth, at altitudes up to 700 metres.

Description –
The Arenga microcarpa is a monoecious and monocarpic palm with multiple stems (dominant 1-3) up to 7 m tall with numerous suckers around the base, stems up to 15 cm of diameter.
The leaves are pinnate, up to 4 m long; leaflets are 78-142 per leaf (about 30-70 pinnae on each side of the leaf), narrow, stiff, pleated, dark green above and paler below, with serrated tips growing from the rachis at an angle of 30° to create a V-shaped leaf. The terminal leaflets are fused at the base and fishtail-like. The fins are grey-green on the underside.
The inflorescence is present from the upper foliar bases and progressively along the stem, 1-2 m long, with 38-44 unbranched hanging panicles of yellowish male and female flowers. The sepals and petals are 3. The flowers are in clusters of 3, a female flower and 2 male flowers.
The fruits are globose, white to red when ripe, 5-18 mm wide. with 1-3 seeds per fruit. The pulp is very irritating due to the presence of calcium oxalate crystals, therefore to be handled with caution, possibly wearing gloves.
Seeds are hard and smooth, globular to angled.

Cultivation –
Arenga microcarpa is an evergreen palm that is harvested from the wild for local use as a food and source of materials. It is sometimes grown locally in its range for starch production and, in addition, all species in this genus have recognized or potential ornamental value.
In fact, despite not being much cultivated outside its origin zones, it is a species of great ornamental and landscaping value, cultivable in full sun or slightly shaded in the tropical subtropical climate zones and, marginally, in the warm temperate climate, as it tolerates temperatures up to at about -3 °C, even if with damage to the foliage. It can be utilized both as an isolated specimen, in spacious gardens, and as a barrier.
This palm can also be grown indoors and is also tolerant of low light, but does best in a sunny, tropical location with plenty of water, and grows quite quickly to produce a good sized plant over a number of years. It grows best in a porous, sandy, humus-rich substrate.
Individual stems do not flower until they are mature. A flowering shoot is produced from each node on the stem, starting at the node at the top of the plant and working down to the base. Vegetative growth ceases when the first flowering shoot is produced and the stem dies once flowers have been produced from the basal node.
However multi-stemmed species usually produce new stems and therefore the plant does not die when the single stems die.
The plant reproduces by division and by seed which germinates in 2-5 months or more; in order to attempt to accelerate germination, the seeds, cleaned of the residues of the pulp with the precautions indicated above, must be immersed in water for 5-6 days, taking care to renew it daily to avoid the proliferation of pathogenic microorganisms. Growth is initially slow, then proceeds quickly in a rather particular way, only 1-4 stems rise quickly, surrounded by the others who remain low, when one dies, after having completed the maturation of the stems, it is replaced by one of the tuft which takes precedence over the others.

Customs and Traditions –
Arenga microcarpa is a plant known by various names, among which we mention: aren sagu, arrack palm, small-fruited areng palm, toddy palm, wild sagu (English); sagu-miúdo (Portuguese).
As for other palms of the genus Arenga, the pith is used by the local populations for its high carbohydrate content (sago) and the young shoots are eaten cooked as vegetables.
The taller Arenga palms store large quantities of starch in the stem which are then transformed into sugar to be translocated into the inflorescences. Sugar can be extracted in the juice by tapping the peduncle and rachis of the male inflorescence. By far the most important sugar producer of the genus is Arenga pinnata, but other species, such as this one, are used in a similar way. The starch from the stem can also be harvested. The starch in the stems of this species, for example, is used in North Sulawesi to bake biscuits known as “bagea”.
The apical shoot (known as “palm heart”) of all species of this genus is edible and is used as a vegetable. However, the consumption of large quantities of gems is not recommended since, in some species (especially Arenga tremula) they can cause toxic effects.
It should be remembered that the collection of the apical shoot also leads to the death of the single stem, as it is unable to produce lateral shoots.
The fruits of most species of this genus are poisonous and are sometimes used criminally; among other things, the fleshy mesocarp of the fruit usually contains many oxalate crystals, making the pulp inedible.
However, no medicinal uses are known.

Method of Preparation –
The Arenga microcarpa is a palm which, in the areas of origin, is used for food purposes. In fact, the marrow is used by the local populations for its high carbohydrate content (sago); even the young shoots are eaten cooked like vegetables.
Sugar can also be extracted from this palm, the procedure generally follows the following phases:
1. Stem Harvesting: The mature stems of the plant are harvested. These barrels are high in starch, which will be converted into sugar during the extraction process.
2. Cutting of the stems: The stems are cut into small pieces to facilitate subsequent processing.
3. Maceration: The stem pieces are immersed in water for an extended period of time. During steeping, the starch in the barrels dissolves in the water, forming a mixture called “sago”.
4. Sieving: After steeping, the blend is sieved to separate the sugary liquid, known as “sago juice,” from the remaining fiber. Sago juice contains dissolved starch and other sugar components.
5. Filtration: The sago juice obtained is filtered to remove any impurities and residual solid parts.
6. Heating: The strained sago juice is heated to help separate the starch from the other components. During heating, the starch settles at the bottom of the container.
7. Decantation: The clear liquid, which contains dissolved sugar, is separated from the deposited starch by decantation or by using separation devices such as centrifuges.
8. Evaporation: The sugary liquid then undergoes an evaporation process to remove excess water and concentrate the sugar content. This can be done by applying heat or using vacuum evaporation techniques.
9. Crystallization: The sugar concentrate is cooled and stirred to promote the formation of sugar crystals.
10. Crystal separation and drying: The formed sugar crystals are separated from the stock solution and subsequently dried to remove residual moisture.
11. Packaging: Finally, the sugar obtained is packaged in suitable containers for distribution and marketing.
It is important to note that the exact procedure for extracting sugar from Arenga microcarpa can vary slightly depending on local practices and the techniques used.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/24807025/original.jpeg
– https://medialib.naturalis.nl/file/id/L.1410267/format/large

Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.