Anacardium occidentale L.

  • Authority

    Mitchell, D. J. & Mori, S. A. 1987. The cashew and its relatives (Anacardium: Anacardiaceae). Mem. New York Bot. Gard. 42: 1-76. (Monograph of the genus Anacardium (Anacardiaceae).)

  • Family

    Anacardiaceae

  • Scientific Name

    Anacardium occidentale L.

  • Description

    Species Description - Small trees, 1.5 to 10(-15) m x 40 cm, with broad crown and tortuous branching. Bark brown or gray, smooth with scattered lenticels to rough with longitudinal fissures, the inner bark thick, pale pinkish-orange to reddish-brown. Leaf blades narrowly to broadly obovate, sometimes broadly oblong, occasionally ovate or elliptic, 6.9-24 x 3.4-11.8 cm, chartaceous to coriaceous, occasionally undulate, glabrous on both surfaces, with 8-18 pairs of lateral veins, these prominent abaxially, prominulous adaxially, the midrib impressed to prominulous adaxially, very prominent abaxially; base cuneate or obtuse, occasionally attenuate or auriculate, frequently asymmetrical; apex usually rounded or obtuse, sometimes shortly acuminate, shallowly emarginate or truncate; petioles 3-25 mm long. Inflorescences sparse to congested, 11-29 x 4.524.5 cm, sparsely puberulous to densely puberulous toward apices of rachises, peduncle 16 cm long, upper bracts lanceolate to ovate, sepal-like, lower bracts obovate, leaf-like, often cream or light green adaxially, pedicels 2.3-5 mm long, sparsely to densely puberulous. Bisexual flowers: corolla cylindric, 3-5 mm diam.; sepals lanceolate to narrowly ovate, 3-6.5 x 0.8-2.0 mm, puberulous adaxially; petals reflexed, linear to lorate, (7-)8-13 x 1-2 mm, puberulous on both surfaces, white or pale green, often with pink or red lines at anthesis, turning dark red after fertilization; stamens 6-10(-12), with one, rarely two, stamen(s) much longer, the largest filament(s) 7.3-11.5 mm long, the remaining filaments much shorter, 2-4 mm long, all filaments with normal anthers; staminal tube 0.3-0.9 mm long; ovary 1.5 x 2.7 mm, the apex glabrous, the style central, awl-shaped, 5.7-8.5 mm long, the stigma punctiform. Staminate flowers with pistillode 0.3-1 mm long. Hypocarp pyriform, much larger in cultivated forms than in wild populations, 5-20 x 2-8 cm, yellow, orange, or red. Drupe subreniform, 2-3.5 x 1-2 cm, gray or brown at maturity.

  • Discussion

    Cassuvium pomiferum Lamarck, Encycl. 1(1): 22. 1783. Type. Sri Lanka. Without date (fl), Fl. Zeylanica 165 in Hermann Herb. 3: 50 (Lectotype, BM!, here designated). Acajuba occidentale (L.) Gaertner, Fruct. sem. pl. 192, t. 40. 1788. Anacardium occidentale Linnaeus var. americanum de Candolle, Prodr. 2: 62. 1825. Type. “Caribaeis et in vicinia continente” (Lectotype, Tabula 181, fig. 35 in Jacquin, Select, stirp. amer. hist. 1763, here designated). Anacardium occidentale Linnaeus var. indicum de Candolle, Prodr. 2: 62. 1825. Type. Indonesia. Molluccas: Amboina Island (Lectotype, Tabula 69 in Rumphius, Herb. Amboin. I. 1741, here designated). Anacardium mediterraneum Vellozo, Fl. flum, 163. 1829 (1825); Vellozo, Fl. flum. Icon. IV, t. 46. 1831 (1829). Type. Brazil. Rio de Janeiro: Exact localityunknown (Lectotype, Tabula 46 in Vellozo, here designated). Anacardium curatellaefolium A. St. Hilaire, Ann. Sc. Nat. Sér. I, 23: 272. 1831. Type. Brazil. Goiás: Plateau of Forquilha, Jaraguá, 1816-1821 (fl), St. Hilaire 854 (Lectotype, P!, here designated; Isolectotypes, F!, P!). Cassuvium reniforme Blanco, Fl. Filip., 322.1837. Type. None cited. Anacardium occidentale Linnaeus var. longifolium Presl, Bot. Bemerkungen Praha, p. 40. 1844. Type. Mauritius. 1834 (fl), Sieber Fl. Mauritius II no. 290 (Lectotype, NY!, here designated). Anacardium subcordatum Presl, Bot. Bemerkungen Praha, p. 40. 1844. Type. Brazil. Bahia: Lhotsky s.n. (Holotype, PR, n.v.). Anacardium occidentale Linnaeus var. gardneri Engler in A. et C. de Candolle, Monogr. phan. 4: 220. 1882. Type. Brazil, Ceará: Catingas of Crato, without date (fl), Gardner 1839 (Holotype, K!). Anacardium microcarpum Ducke, Arch. Jard. Bot. Rio de Janeiro 3: 202. 1922. Type. Brazil. Pará: Monte Alegre; campo, 19 Sep 1916 (fl), Ducke s. n. MG 16516 (Lectotype, RB!, here designated). Anacardium rondonianum Machado, Arch. Jard. Bot. Rio de Janeiro 9: 87. 1949. Type. Brazil. Goiás: “Cidade Aruanum Cantigua Leopoldina, na confluência do Rio Vermelho com o Araguaia,” 12 Aug 1945 (fl), Machado 221 (RB 57500) (Holotype, RB!; Isotype, K!). Anacardium amilcarianum Machado, Arch. Jard. Bot. Rio de Janeiro 9:88. 1949. Type. Brazil. Goiás: “Ilha do Bananal, Posto Serviço de Proteção aos índios, Santa Izabel,” 23 Aug 1945 (fl), Machado 205 (RB 57501) (Holotype, RB!; Isotypes, F!, K!). Anacardium kuhlmannianum Machado, Arch. Jard. Bot. Rio de Janeiro 9: 89. 1949. Type. Brazil. Goiás: “Ilha do Bananal, no cerrado junto ao porto de acesso à casa da Fazenda do Porto Indígena de Santa Izabel,” 23 Aug 1945 (fl), Machado 207 (RB 57499) (Holotype, RB!; Isotype, CEN!). Anacardium othonianum Rizzini, Anais Acad. Bras. Ciénc. 41(2): 243. 1969. Type. Brazil. Goiás: “Depois de Gama,” 28 Sep 1968 (fl, fr), Rizzini s.n. (RB 140118) (Holotype, RB!; Isotype, CEN!). The natural distribution of A. occidentale extends from northern South America south to São Paulo, Brazil (Map 2). It is probably not native to Central America, the West Indies, or South America west of the Andes. We believe that A. occidentale originally evolved in the cerrados of Central Brazil and later colonized the more recent restingas of the coast. Central Brazil is a center of diversity for Anacardium where the distribution of A. occidentale overlaps the ranges of A. humile, A. nanum, and A. corymbosum. Anacardium humile, the closest relative of the cultivated cashew, is closer morphologically to the cerrado ecotype than it is to the restinga and cultivated populations of A. occidentale (Table IV). Ecologically, the cashew is very adaptable as it can tolerate extended periods of drought and poor soils (pH 4.5-6.5). The most important limiting factors in its growth are water-logged or calcareous soils and frosts (Johnson, 1973; Martin, 1984; Opeke, 1982). Cold has the most severe effect on young trees (Morton, 1961) and this probably limits the species to less than 1500 m above sea level. In the Greater Antilles, A. occidentale flowers from December to August with peak flowering from February to April. A secondary flowering peak occurs in August. Fruits usually are produced from February to August. In the Lesser Antilles, flowering occurs from November to August with peak flowering from February to May. The Central American populations generally flower from December to May with peak flowering from January to April and fruiting from December to July. In Colombia and Venezuela, flowering and fruiting is either distributed throughout the year or varies regionally, and, in the Guianas, flowering and fruiting occurs throughout the year with peaks in April to July and from September to November. The eastern Amazonian populations of A. occidentale flower from December to February and from May to October with peaks in January and from July to September. In western Amazonia, flowering occurs throughout the year with peaks from February to June and from August to October. In northeastern Brazil flowering occurs throughout the year with a peak from June to December. In southeastern Brazil, flowering is throughout the year with peaks in January and February and September and October. Fruiting is primarily from November to April. In central Brazil, flowering mostly occurs from June to October with the majority of the fruit produced in October. In general, throughout its range A. occidentale flowers most profusely during the dry season. In many areas, two fruit crops are produced yearly. Flowering is controlled by several environmental cues. An increase in sunshine and moisture stress concomitant with a decrease in relative humidity following the end of the rainy season induces bud break. Then, a new flush of leaves is produced which is directly followed by flowering (Allen, 1956). Low temperatures, however, delay flowering (Nambiar, 1977). Staminate flowers open before bisexual ones (Thimmaraju et al., 1980). Most cashew flowers open between 0600 and 1800 with peak anthesis occurring between 1100 and 1230. The stigmas are receptive as soon as the flowers open and the anthers dehisce one to five hours later (North-wood, 1966). Anacardium occidentale is highly out-crossed. Experiments have shown that maximum fruit set (80%) is obtained by crossing emasculated flowers with pollen from another plant, whereas self-pollinated flowers gave a much lower fruit set (40%) (Thimmaraju et al., 1980). The flowers are pollinated by bees, wasps, ants, flies, and possibly hummingbirds (Free & Williams, 1976; Johnson, 1973). In cashew plantations, most of the pollination is accomplished by honey bees (Free & Williams, 1976). Natural populations of A. Occident ale are pollinated by bees and butterflies (Mitchell & Mori, pers. obs.) The primary dispersal agents of the fruits of A. occidentaleare probably frugivorous bats (Ay-ensu, 1974; Bates, 1864; Racey & Nicoll, 1984; M. Tuttle, pers. comm.; Wilson, 1971) (Fig. 14). Bats fly into a tree or shrub, seize the fruit, eat the fleshy hypocarp, and then discard the poisonous drupe (Wilson, 1971). Bat dispersal also has been reported for A. excelsum and bats are probably the primary dispersal agents for most species of the genus. However, water has been suggested as a secondary means of dispersal (Ding Hou, 1978; Johnson, 1973). Pathology. A comprehensive review of the pathology of Anacardium occidentale is beyond the scope of this monograph. Most of the research on the diseases and pests of A. occidentale has been conducted in plantations outside of its natural range. Common insect pests on A. occidentale in West Africa include representatives from the following families: Cerambycidae, Noctuidae, Thripidae, Scarabalidae, Pyralidae, Acrididae, and Psyllidae (Opeke, 1982). Some insect pests are widespread, for example the red-banded thrip (Selenothrips rubricinctus) attacks A. occidentale in West Africa and in the West Indies (Opeke, 1982; Popenoe, 1920). An extensive list of insects associated with the fruits, leaves, and wood of A. occidentale is found in Baccari and Gerini (1968). Mites (Acari) are major pests of A. occidentale (Aquino & Arruda, 1969; Arruda & Aquino, 1970; Bano & Nagesha Chandra, 1973; Rodrigues, 1967, 1970). However, Rodrigues (1967) points out that some mites are beneficial associates. Fungi are the primary causes of death, declining productivity, and poor quality of fruits of A. occidentale. Fungal diseases of major importance include “fruit rot” which is caused by several species of fungi, “decline” (Pythium spinosum Saw.), “sudden death” (Valsa eugeniae Nutman & Roberts), and “anthracnose” (Colletotrichum gloeosporioides Penz.) (Cook, 1975; Martin, 1984; Opeke, 1982). The fungi associated with A. occidentale have been the subject of several recent investigations (Aquino & Melo, 1974; Early & Punithalingham, 1972; Mhaskar & Rao, 1975; Sathe & Moqarkar, 1975; Wani & Thirumalachar, 1969). Some of the fungal diseases are easily avoided. For example, “seedling wilt” (Fusarium spp.) is controlled by reducing watering of seedlings in the nursery. Similarly, “fruit rot,” which is characterized by the fruits rotting before ripening, is common only in high rainfall areas (Opeke, 1982). Local names and uses. Acajú, derived from the Tupi Indians of Brazil (Johnson, 1973), became cajú in Portuguese and variants of cajú in tropical Asian and African countries. The English name cashew is clearly derived from the Portuguese cajú. Belize: Cashew. Bolivia: Marañón. Brazil: Acajaiba, cajueira, cajueiro, cajueiro azêdo, cajueiro doce, cajú, cajú amarelo, cajú banana, cajú da praia, cajú do campo, cajú manga, cajú vermelho, cajuhy, cajuhy azêdo, cajuhy doce, oa-caju, rabuno-eté (Carajá Indians). Colombia: Marañón, merey. Costa Rica: Marañón. Cuba. Cajuil, marañón. Dominican Republic: Cajuil. French Guiana: Acajou, acajou à pomme, ana-cardier, cassoun. Guatemala: Jocote marañón. Guyana: Cashew. Honduras: Jocote marañón. Jamaica: Cashew. Mexico: Marañón. Peru: Casho, casú, marañón. Puerto Rico: Pajuil. Surinam: Bosch kasjoe, kadjoe, kasjoe, mereke, olojé koe, olvi, orvi, sabana kadjoe. Trinidad and Tobago: Cashew. Venezuela: Marañón, merey. In Brazil, the cashew nut is called castanha and the hypocarp is frequently referred to as cajú manso. The name jocote marañón used in Guatemala and Honduras implies that the natives are aware of the relationship between A. occidentale and Spondias mombin L. (local name jocote). Selected Old World names. ASIA. Burma: Sih-osayesi, thee-noh, thi-ho-thayet, tihotiya-si. China: Kia jou chou, tu hsien tzu. India: Agni-krita, guchapushpa, hajli badam, jidi-mamadi, kaju, kaju kalinga, kajutaka, keré-mara, paran-gimaru, prithagabija, sophahara, vrittapatra. Indonesia: Buwa jaki, buwah monjèt, djambu dipa, djambu djipang, djambu gadjus, djambu monjèt, djambu parang, djambu sèmpal, djambu séran, djanggus gadjus, kanoké, masapana, njambuk njebèt, wojakis. Malaysia: Gajus, jagus, keterek. Philippines: Balógo, bálubad, balúgo, casuy, ka-chui, kasói, kasul, kosing, sambalduke. Sri Lanka: Caju, cashew-nut, montin-kai. Vietnam: Cây dau lôn môc, da lôn hôll. AFRICA. Seychelles: Bois cachou. Tanzania: Mbibo, mkanju, mko-rosho. South Africa; Zululand: Mkatshu. The economic botany of A. occidentale is a broad subject and therefore a comprehensive review cannot be attempted here. Instead, selected information about the uses of the species will be summarized and selected references will be given in order to indicate where more thorough treatments may be found. The cashew was introduced from Brazil into India and East Africa by the Portuguese (Johnson 1973; Popenoe, 1920; Woodruff, 1979) and today India, East Africa, and Brazil are the world’s largest producers (Martin, 1984; Opeke, 1982). India, with its extensive orchards and modem processing machinery, is the chief center of cashew production. Tanzania exports more than 70,000 tons of nuts, yet most of the plantings are on farms of only a few acres (Schery, 1972) and the country exports a large proportion of its unshelled cashews to India for processing (Woodruff, 1979). The annual world production of cashew nuts is approximately 250,000 tons (Opeke, 1982) which places it second to the almond in world trade in tree nuts (Schery, 1972; Woodruff, 1979). The fruits are harvested after they fall to the ground. The drupes or “nuts” are sun dried for two days to decrease moisture content by 16-17% for safe storage. The drupes are cleaned and the fruit wall is cracked to liberate the kernel. Cashew nut shell liquid (CNS liquid) is extracted from the fruit wall. After removal, the kernel is dried and the testa is peeled off (Woodruff, 1979). The peasant method of processing cashew nuts consists of the drupes being roasted in shallow pans over open charcoal fires which is dangerous because the liberated fumes are caustic. After the drupes are roasted they are cracked and hand shelled. The workers’ hands are protected by periodically dipping them in linseed or castor oil (Schery, 1972; Woodruff, 1979). Today, processing equipment in modem factories has been improved to protect the worker from the toxic fumes and to recover the valuable CNS liquid. From 600 to 1000 nuts per hour can be cracked by modem machines. The industrial production of cashew nuts is discussed in more detail by Woodruff (1979). Cashew nuts are imported in large quantities by the United States and western European countries. The nuts are salted and eaten as a snack and they are used extensively in the manufacture of candies, cakes, cashew flour, and cashew butter. The protein content of the kernel varies from 13.3 to 25.03% (Mohapatra et al., 1972). The nuts are very nutritious, containing vitamins A, D, and K and between 200-210 mg/100 g of vitamin E. Substantial amounts of calcium, phosphorus, and iron are also present. Cashew nuts are highly recommended because, in contrast to the peanut, there is no risk of aflatoxin poisoning (Opeke, 1982). The cashew nut shell liquid (CNS liquid), contained in the oil cavities of the fruit wall, is a toxic yet very important by-product of the cashew industry. CNS liquid consists primarily of cardol, cardanol, and anacardic acid (Tyman & Morris, 1967). Cardol is structurally related to urushiol of Toxicodendron radicans (L.) O. Ktze., and it is the principal cause of dermatitis due to the handling of cashew nut shells (Woodruff, 1979). The CNS liquid is used in the manufacture of plastics, paints, resins, and varnishes (Lossner, 1971; Woodruff, 1979). In Tanzania, CNS liquid has been used for making tribal marks and scars on the face and body and, in other countries, it is employed in preserving fish nets, protecting books, and in softening chicken eggs. Anacardic acid, the active ingredient in CNS liquid, is an effective larvicide used in the control of malaria-carrying mosquitoes (Isao Kubo, as reported in the New York Times, 4 Dec 1984 and in The Chronicle of Higher Education, 12 Dec 1984; Joseph, 1967; Watt & Breyer-Brand-wijk, 1962). Anacardic acid also kills the snail hosts of schistosomes (Isao Kubo, ibid.; Sullivan et al., 1982) and inhibits the metabolism of several species of bacteria and molds (Gellerman et al., 1969). CNS liquid is useful as an anthelmintic against ascaridiasis (Varghese et al., 1971). The hypocarp is succulent, sweet to very acidic in taste, and very fragrant. It is either eaten raw, compressed and strained to extract juice (cajuada in Brazil), fermented into cashew wine, or made into syrup, preserves, chutney, candy, pickles, or used as an ice cream flavor (Martin, 1984; Schery, 1972; Woodruff, 1979). The hypocarp, often called the cashew apple or pear, is a rich source of vitamin A (Cecchi & Rodriguez-Amaya, 1981) and vitamin C (Falade, 1981) which occurs at a concentration of 180 mg/100 g (Martin, 1984). In some countries, such as Brazil, the drupe is less important than the hypocarp (Woodruff, 1979). Medical uses of the hypocarp are varied and include the following: mouth wash and gargle; boiled in sweetened water and used as a treatment for dysentery (Perry & Metzger, 1980); treatment for uterine ailments and dropsy; and as a diuretic (Watt & Breyer-Brandwijk, 1962). Hypocarp tannins are used as an anti-hypertensive (Paris et al., 1977). The young leaves are edible (Meijer, 1983) and older leaves in combination with other plants are used to treat skin diseases and burns (Perry & Metzger, 1980). The bark has a variety of medicinal uses such as: the treatment of diarrhea and constipation (Perry & Metzger, 1980); a gargle; a treatment for ulcers in the mouth; a febrifuge; a medication to lower blood sugar (Watt & Breyer-Brandwijk, 1962); and a cure for toothache and sore gums (Kirtikar et al., 1935). The bark and inflorescences are used in traditional Indian remedies for snakebite (Kirtikar et al., 1935). The sap, which oxidizes black upon exposure to the air, is employed as an indelible ink marker for cottons and linens. It is also used as a varnish and a flux to solder metals. A gum, which exudes from the bark, is used as a substitute for gum arabic in book binding (Woodruff, 1979). The wood is employed locally for construction, storage cases, boats, wheel hubs, and as a fuel (Benza, 1980; Woodruff, 1979). Although A occidentale is cultivated primarily for its kernel and fleshy hypocarp, it is occasionally used for reforestation in tropical America (Lamprecht, 1958) and in Dahomey (Williams, 1969). Although of tremendous economic importance, no work has been done with the infraspecific classification of A. occidentale. Fewcultivars have been named and the only major distinction established is that between yellow and red hypocarp cultivars. Some trees have been selected for nut quality, whereas others have been selected for hypocarp size, color, succulence, and flavor. This monograph does not address the problem of intraspecific variation in A occidentale. This topic remains as an important and exciting area for future research. Cultivation. The optimum temperature for seed germination is 35°C (Rocchetti & Panerai, 1968). The seed coat delays germination for several weeks but earlier germination is promoted by various treatments which are summarized by Opeke (1982). Trees come into flower and fruit within three to four years from seed and within two to three years after vegetative propagation (Benza, 1980; Martin, 1984; Popenoe, 1920). In plantations, cashew trees should be planted far enough apart to enhance root extension which in turn insures maximum fruit production (Dagg & Tapley, 1967; Northwood & Tsakiris, 1967). Opeke (1982) recommends a spacing of between 9 x 9 m to 12 x 12m for mature trees. Typical yields are between 700 to 900 kg of whole nuts or 150 to 300 kg of shelled nuts per hectare (Martin, 1984). The vegetative propagation of high yielding, good quality trees by grafting, layering, and cuttings is recommended (Nambiar, 1977). Taxonomy. After consultation with C. Jarvis (of the lectotypification of Linnaean names project), we have designated Flora Zeylanica 165 in Hermann Herbarium 3:50 (BM) as the lectotype for A. occidentale. Fawcett and Rendle (1926) cited the Hermann Herbarium specimens as the type for A. occidentale, and they also referred to a specimen determined by Linnaeus in the Linnaean Herbarium. The senior author recently examined specimens 534-1 and 534-2 at LINN. The specimens of A. occidentale at BM and LINN are apparently the only extant sheets seen by Linnaeus (C. Jarvis, pers. comm.). Because a specimen is preferred over the illustrations cited by Linnaeus (1753), we have chosen the BM collection of Zeylanica 165 as the lectotype. We have chosen St. Hilaire 854 (P) as the lectotype for A. curatellaefolium St. Hilaire. Although St. Hilaire did not list syntypes in the protologue, he collected the specimen and it is annotated as A. curatellaefolium in what appears to be his handwriting. In addition, the gross morphology of the St. Hilaire 854 specimens corresponds very closely with the diagnosis. Anacardium occidentale is a polymorphic species. The restinga ecotype of A. occidentale oí eastern coastal Brazil is easily differentiated from A. humile. However, the cerrado ecotype of A. occidentale sometimes overlaps in leaf morphology with A. humile (Fig. 20, Table IV). The principal difference between A. occidentale and A. humile is that the former is always a tree (Fig. 1) and the latter is a subshrub with a massive underground root system and rigidly ascending branches (Fig. 2A). The cerrado ecotype of A. occidentale frequently has broadly obovate leaves with an obtuse or slightly auriculate base, whereas the leaves of A. humile are generally oblanceolate with attenuate bases. Moreover, the majority of flowers of A. occidentale have 9-10 stamens while the majority of flowers of A. humile have 7-8 stamens. If the specimen label does not include information about the plant’s habit, it is often difficult to separate A. occidental from A. humile. The types of A. curatellaefolium St. Hil., A. rondonianum Machado, A. amilcarianum Machado, A. kuhlmannianum Machado, and A. othonianum Rizzini exemplify the cerrado ecotype of A. occidentale.

  • Distribution

    Distribution. Anacardium occidentale is cultivated and adventive throughout the Old and New World Tropics where the geographical limits of its cultivation are latitudes 27°N and 28°S, respectively (Nambiar, 1977). Anacardium occidentale is native to tropical America where its natural distribution is unclear because of its long and intimate association with man. The problem of its origin and distribution has been investigated by Johnson (1972, 1973) who suggested that it originated in the resti