Rukam

What it is

Flacourtia rukam bears round, slightly flattened or drop-shaped fruit, about 2 to 2.5 cm (0.8 to 1 in) across. The ripe skin can be dark red, with whitish flesh beneath it. Four to seven flat seeds sit inside. A small ring of pegs at the top is left over from the flower.

Where it comes from

Rukam grows both wild and cultivated across the Malay Archipelago. It is native to Singapore and has been introduced to India, Thailand and Indochina. In Java it is called rukam; in Malaysia, rukam manis is one of its names. Its forest home is warm and humid, often beside rivers.

How it's eaten where it grows

Alongside rujak, rukam becomes pickles, jam and sweet preserves. In Bengkalis, Riau, Indonesia, home cook Nurfaizah makes manisan rukem, fruit sweetened with sugar. She halves the fruit, takes out the seeds and soaks it in salt water. After a boil of a minute or two, the fruit is drained and left under sugar overnight, until it releases its own juice.

For eating fresh, the palm-rubbing step comes first. It bruises the ripe flesh and removes the mouth-drying quality, leaving the fruit ready to eat raw.

How it's grown

The tree can reach 20 m (66 ft). Young stems and branches carry strong woody thorns up to 10 cm (4 in) long, but trees propagated from a parent plant, rather than from seed, usually lack them. Rukam is usually grown from seed; shoots from the roots are used to multiply thornless trees. In Indonesia they also graft rukam buds onto Flacourtia inermis.

Male trees supply the pollen needed for fruit, and insects visit the flowers for nectar.

When and where you'll find it

In Java, the trees usually flower from June through August, and fruit ripens about 14 weeks later. In its Southeast Asian home, the ripe fruit is eaten fresh or turned into pickles and sweets.