Nephelium mutabile (sometimes classified as N. ramboutan-ake), pulasan, is a tropical evergreen tree in the Sapindaceae (soapberry family) native to and long cultivated in West Malaysia and of regional importance for its edible fruits, which are similar to other fruits in the same family, including rambutan, lychee, longan, and akee (Nephelium lappaceum, Litchi chinensis, Dimocarpus longan, and Blighia sapida, respectively).

Pulasan, which is similar to and sometimes confused with the closely related rambutan, is an attractive, medium-sized tree, sometimes used as an ornamental. It typically grows 10 to 15 m (33 to 50 ft) tall, with a short, slender trunk (30 to 40 cm, or 12 to 16 in, in diameter). The alternate leaves are pinnately compound, with or without a terminal leaflet, with 2 to 5 pairs of opposite to subopposite leaflets, each 6.25 to 17.5 cm cm (2.5 to 7 in) long. The small yellow petal-less flowers are borne in many-branched terminal or axillary (where leaf meets stem) panicles (clusters) that are covered with yellow to brown downy hairs. The fruit is oval, 5 to 7.5 cm long (2 to 2.75 in), with a thick, leathery rind covered with tubercles (warty protuberances) tipped with thick, fleshy spines. The fruit ripens to dark yellow or red on the exterior, within which is a thin layer (less than 1 cm or 3/8 in thick) of white or yellowish shiny, juicy flesh covering a somewhat flattened oval, light brown seed, which is 2.0 to 3.5 cm (0.75 to 1.125 in) long.

Pulasan fruits are generally eaten fresh or may be made into jam. The seeds, which contain edible oils, are sometimes roasted and boiled to make a cocoa-like beverage. They are regionally important in Malaysia, but not as widely cultivated as rambutan.

(Morton 1987, van Wyk 2005.)