Anacardium occidentale L.

A shrub or tree up to 10 m. high; branchlets rather thick, glabrous, striate.. Leaves glabrous; petiole 1–3 cm. long, ± 2 mm. broad at the base, semicylindric; lamina broadly obovate to oblong-obovate, 6.5–18 cm. long, 3.8–10 cm. broad, obtuse to rounded or emarginate at the apex, cuneate or rounded at the base, coriaceous to subcoriaceous and shining; midrib not raised above, very prominent beneath; lateral nerves 9–14 pairs, slightly raised.. Inflorescence 10–25 cm. long, with reddish to blackish ascendent puberulous branches; pedicels ± 0.5 mm. long, puberulous; bracts 5–10 mm. long, 2–5 mm. broad, ovate-lanceolate, densely greyish puberulous outside, glabrous inside.. Calyx-segments 4–5 mm. long, 1–2.2 mm. broad, lanceolate to oblong-ovate, greyish puberulous outside.. Petals linear-lanceolate, 7–13 mm. long, 1–1.7 mm. broad, yellowish white to pale reddish, puberulous on both faces.. Stamens unequal in length, 1–2 with filaments 6–9 mm. long, the others with filaments 2–3 mm. long and sterile anthers.. Ovary of the bisexual flowers obliquely obovoid, puberulous; style ± 4 mm. long.. Fruit on a very thickened fleshy pedicel, kidney-shaped, laterally umbilicate, 2–3 cm. long, 1.5–2.5 cm. broad, greenish yellow.. Seed kidney-shaped, with a reddish brown testa, 2 large white cotyledons and a small embryo.

It is a tropical plant. It suits the lowland tropics but will grow up to about 1200 m altitude. It only bears well in dry areas because of blight of the flowers. It needs warm frost free locations. It grows with temperatures between 22-26°C. A rainfall of 1750 mm per year is considered suitable but good yields have been obtained with rainfall of 750 mm. Wider spacing is needed in drier areas. It can grow on poor soils. It needs good drainage. It is drought resistant. It grows in the Sahel. In South India it grows up to 1000 m altitude. It can grow in arid places. It suits hardiness zones 11-12. In Yunnan.

Uses. All parts of the plant contain an irritant skin poison, but particularly the seed, or kernel of the nut ( CORNER Ways. Trees 1940 100 ). On heating this substance is destroyed, hence cashew nuts must be roasted before being eaten; the raw nut would sear the lips and cannot be swallowed. The fleshy pear-like cushion on which the nut is so characteristically placed, can be eaten raw: it has a delightful fragrance, but in Malayan varieties the taste is poor and the juice sets up a slight irritation in the throat, obliging one to cough. Much better varieties occur in tropical America, where the pulpy part of the cashew apple is extensively eaten.Various parts of the tree are used in native medicine, etc.; for more detailed information on uses, cf. HEYNE, BURKILL, and PURSEGLOVE, ll. cc.

It is usually grown from seeds. Seeds germinate poorly and slowly. Only nuts which sink in water (or a solution of 150 g of sugar in a litre of water) should be planted. Seeds are sun dried for 2-3 days to improve germination. Seeds can be sown in a nursery then transplanted or more commonly are sown directly. Trees are spaced 7-10 m apart. The crop is cross pollinated mostly by insects. It can be propagated by air layering. For good production complete fertiliser or appropriate organic material should be applied. Pruning to shape the tree is often undertaken in the first 2 or 3 years. Cashews are often planted scattered in gardens or amongst other trees. Clearing under the tree prevents fire and makes finding nuts easier. Allowing nuts to fall before harvesting ensures only ripe nuts are collected. Resin in the cashew nut shell can damage hands and discolour the nuts. Roasting the nuts before removing the kernel avoids this.