It's one kind of fruits that is hardly on sale in Singapore. We call it " Buah Longlong", I have been searching for quite sometime, still can not get its English name.
This is one of my favourite plants, it grows well in any kind of container, though the bigger pot is the best for it to grow. I bought the baby plant from Pasar Malam (local night market), it was about 25 inch height in a plastic pot, after one year, it is growing to 1 meter height, flowering and bearing the fruits.
The flowers in light yellow colour. The leaves have very fresh of sour smell. It need a lot of sunlight and water, otherwise the leaves turn brown.
The fruits are similar to the green mangoes, the bigger I have seen is about an egg size, it tastes sour but crunchier, I like to eat it when the fruit is unripe the skin in dark green colour. The fruit change to brownish-yellow colour when it is ripe. The seed is very hard and has lots of fibres.