Marking nut tree commonly known as the, 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.
Marking Nut is a moderate-sized deciduous tree with large stiff leaves. Leaves are 7-24 inches long, 2-12 inches wide, obovate-oblong, rounded a t the tip. Leaf base is rounded, heart-shaped or narrowed into the stalk, leathery in texture. Flowers is small, borne in panicles shorter than the leaves. Fruit is a drupe 1 inch long, ovoid or oblong, smooth and shining, black when ripe, seated on a fleshy cup. The stem yields, by tapping, an acrid, viscid juice from which a varnish is prepared. The nut yields a powerful and bitter substance used everywhere in India as a substitute for marking ink for clothes by washermen, hence it is frequently called Dhobi Nut. It gives a black colour to cotton fabrics, but before application it must be mixed with limewater as a fixator. The fruits are also used as a dye. They are also largely employed in Indian medicine. The fleshy cups on which the nuts rest and the kernels of the nuts are eaten.
The fruit is useful in leucoderma, scaly skin, allergic, dermatitis, poisonous bites, leprosy, cough, asthma, and dyspepsia. It is extremely beneficial in the diseases like piles, colitis, diarrhea, dyspepsia, ascites, tumours and worms. The topical application of its oil on swollen joints and traumatic wounds effectively controls the pain.