I always like to compare having a rambutan tree in our Sarawakians’ house compound to that of an apple tree in an English backyard garden. Most owners of landed property in Sarawak would most likely choose a rambutan tree in very much the same way as the English would choose an apple tree for his garden when they intend to grow a fruit tree.
Just like the apple tree, the rambutan tree is such a sight to behold when it is laden with ripen fruits.
The domesticated rambutan is scientifically known as Nephelium lappaceum and belongs to the family Sapindaceae (to which lychee and longan also belong). There are many wild relatives of rambutan in Sarawak and Borneo.
Sibu is named after the wild rambutan called Sibau (Iban) which is scientifically known as Nephelium reticulatum. The Malays refer to it as Sibo. Very old colonial map has Sibu spelt as "Siboe". How it later appeared as Sibu on the map is anybody's guess but it could be a mispronounciation or more likely Sibu is the English spelling which is meant to be pronounced as 'Sibo'. (Many words in Iban that end with "au" end with an "o" in Sarawak Malay dialect eg bakau is bako, pulau is pulo and so forth). It is interesting to note that older generation of Hokkiens and Malays still refer to Sibu as Sibo while those eldery ibans still refers to Sibu as "Sibau".
It is possible that Sibau was once abundant in and around Sibu town, particularly on the often inundated bank of the Rejang River and the peat swamp areas.
Sarawak is not alone in having a town name after the wild rambutan. There is also a place in West Kalimantan, Indonesia called Putus Sibau
Rambutan or "the hairy fruit"
Ever wonder why the fleshy part of the rambutan fruit is difficult to detached from the seed unlike longan even though both belong to the same family? The reason is because the fleshy part of rambutan is developed from or is part of the seed coat (testa) unlike the fleshy part of longan which is not part of the seed coat. So, the fleshy part of rambutan is also known as “sarcotesta”. Even in the best rambutan variety whereby the flesh detached off from the fruit much more easily, the seed coat is still attached to the fleshy part.
The seeds of rambutan is said to be rich in solid fat which can be used to make soap and candle but is not popular as it is not commercially viable. Rambutan can also be made into jam but has not been popular.
It is interesting to note that Obama missed rambutan and will try it with fried rice when he intends to visit Indonesia where he spent part of his childhood.
Another lesser known wild rambutan species which is more spiky than hairy but is gaining popularity is the Pulasan or Nephelium rambutan-ake.
pulasan or Nephelium rambutan-ake
There is another species of rambutan which is hardly hairy at all: Nephelium maingayi. Its Iban name is mujau and the melanau called it serait.