Semecarpus anacardium

Semecarpus anacardium, commonly known as the marking nut tree, Malacca bean tree, marany nut, oriental cashew, phobi nut tree and varnish tree, is a native of India, found in the outer Himalayas to the Coromandel Coast. It is closely related to the cashew.

Etymology
Semecarpus anacardium was called the "marking nut" by Europeans because it was used by washermen to mark cloth and clothing before washing, as it imparted a water insoluble mark to the cloth.

The specific epithet anacardium ("up-heart") was used by apothecaries in the 16th century to refer to the plant's fruit. It was later used by Linnaeus to refer to the cashew.

Description
It is a deciduous tree. Like the closely related cashew, the fruit is composed of two parts, a reddish-orange accessory fruit and a black drupe that grows at the end. The nut is about 25 mm long, ovoid and smooth lustrous black. The accessory fruit is edible and sweet when ripe, but the black fruit is toxic and produces a severe allergic reaction if it is consumed or its resin comes in contact with the skin. The seed inside the black fruit, known as godambi (गोडंबी), is edible when properly prepared.

Uses
In medieval times, Semecarpus anacardium was thought to aid in memory retention, for which cause the following dictum became widespread among Jewish scholars: "Repeat [your lessons], and repeat [your lessons], but never stand in need of the marking nut!"