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11 STAR APPLES Two common dooryard trees in tropical American countries are the star apple (Chrysophyllum cainito) and satinleaf (C. oliviforme). Everybody loves having them grow near the house. Their leaves are deep green on top and have a satiny coat of golden brown shiny hairs underneath. Wind rustling the foliage creates a striking effect as the green and gold flash sequentially in the sunlight.1 In addition, these beautiful trees produce some of the most beloved local fruits. Their apple-sized delights have a sweet flesh with small seeds arranged in a typical star pattern. Both trees are widely planted in the Americas. They grow rapidly, often rising more than a meter each growing season. Once established, they become almost trouble free, resisting among other things pests, diseases, and high winds. As long as they remain unexposed to freezing temperatures, they burden the grower with almost no problems and continue to produce quantities of delicious fruit year after year. What is not well known is that Africa has its own counterparts. The vastnesses below the Sahara contains more than a dozen species related to the American star apple and satinleaf.2 These too are attractive trees producing delicious fruits. They also are candidates for producing trouble- free dooryard delights, and perhaps more. But these African relatives remain horticulturally undeveloped and their nutritional qualities are not yet clear. Despite neglect, Africa’s star apples are esteemed in many places. The fruits are green, purple, apricot, yellow, or copper in color. Their smooth skin encloses a white, sweet-tasting pulp arranged in segments. Cut transversely, most of them display the family crest: the star-shaped arrangement of seeds. The pleasantly acid pulp is almost always eaten fresh. Clearly, the various African species deserve at least preliminary horticultural and nutritional investigation. An overarching requirement for 1 For this reason, star apple is also called golden leaf tree. Victorian novelist Charles Kingsley described it as, “like an evergreen peach, shedding from the underside of every leaf a golden light—call it not shade? A star apple.” 2 Some botanists divide African star apples among different genera: Chrysophyllum, Bequaertiodendron, and Manilkara. Gambeya is a synonym sometimes used for Chrysophyllum (especially in the tropical-wood trade). Family: Sapotaceae. 317

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LOST CROPS OF AFRICA 318 Equateur Province, Congo D.R. Despite the fact that African star apples are currently unexplored and their value in organized plantings untried, they hold promise. They produce delicious fruits that are popular wherever they are grown. Selecting elite cultivars could create new consumers both locally and in far-away places. (Roy Danforth and Paul Noren) greater progress is genetic selection. A huge diversity of different types exists. Fruits can be found, for instance, in an array of colors, shapes, sizes, and tastes. The trees also exhibit differing sizes, forms, features, and productivities. Some trees, for example, fruit heavily, others lightly. Little of this genetic wealth has been evaluated or even explored, let alone exploited. Although named varieties and organized production are now unknown, superior plants are to be found and almost certainly can be propagated vegetatively. This needs doing. Elite clones will likely transform this wild crop by raising quality and reliability as well as by yielding fruits at a much younger age. Budgrafting white star apple, for example, has produced fruiting within 3 years in Nigeria.3 When superior fruits become available they seem likely to find ready outlets in both subsistence and commerce. However, at present not even the basics of production and use are well described. Little is known, for example, about the management of the trees, let alone the nutritional qualities of the fruits. Probably, though, the nutritional composition is not too different from those in American star apple, which is much like that of citrus fruit, except for the vitamin C which is less than half that in oranges. 3 Information from J.C. Okafor. Other vegetative methods likely to succeed are air- layering (marcotting), cuttings, and tongue-inarching.

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STAR APPLES 319 One particular problem is that the fruits must be allowed to ripen on the tree; when picked immature they are sticky with latex and astringent to the palate. Today, they are allowed to ripen and fall, and are then picked up from the ground. It seems likely that this process can be improved upon. Probably, fruits can be picked immature and subsequently ripened using ethylene—a gas now widely used to ripen oranges, tomatoes, and other fruit on demand. This would extend the shelf life as well as the distance they could be shipped to market. For their ornamental value alone these trees merit attention. They might make useful reforestation species as well. Fully grown, they reach up to 30 m in height and 2 m in girth, and their hard, white wood is famous for quality. It is in international demand, and is traded under the name longhi (or longui). One website touts it for “interior joinery, furniture components, domestic flooring, stairs, decorative sliced veneers, plywood, interior fittings, turnery, construction, vehicle bodies, handles, sporting goods, carvings, agricultural implements.” Particularly promising for investigation are the following: White Star Apple This forest tree (Chrysophyllum albidum G. Don) is native across much of tropical Africa. In recent times, however, it has sadly become uncommon in the wild. Today, it occurs mostly in villages, where it tends to exist as solitary specimens. In southern Nigeria and other areas of West Africa, such household plantings are the only remnants of what was once a common forest occupant. In those villages, however, the people look after the tree, commonly managing it in at least a rough-and-ready manner. During the harvest season the fruits are put on sale, but mostly only in nearby villages; seldom are they shipped even to the cities. That is a pity because this fleshy, juicy fruit is wildly popular. It is nearly spherical, slightly pointed at the tip. When ripe, it is orange-red, yellow, or yellow- brown in color, sometimes with brownish speckles. Inside is a yellowish pulp surrounding five brown seeds arranged in the regular star shape. To eat the fruit people first split it open, usually by squeezing it between the fingers of both hands. This exposes the pulp, which is commonly the color of flesh and tears apart not unlike meat. This very tasty fruit flesh is eaten directly, but only after any milky sticky juice has dripped away. It is said to have potential as a soft-drink flavoring. It is even now fermented into wine and sometimes distilled into spirits. High in pectin, it forms an excellent jam, said to have a shelf life of up to a year even in the tropics. In some areas the white star apple is exclusively a food of children, some of whom prefer to chew the immature fruit, which at that stage is like gum.4 4 This is not as unusual as might at first appear. These fruits are part of the same family

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LOST CROPS OF AFRICA 320 Fruits of white star apple (Chrysophyllum albidum). African star apples remain horticulturally undeveloped and their nutritional qualities are undocumented. Despite scientific neglect, however, they are esteemed in many places, are likely to have nutritional merit of at least a modest nature, and good selections undoubtedly await recognition among its vast genetic diversity. (J.D. Mollon/Petroc Sumner, http://vision.psychol.cam.ac.uk/jdmollon) However, in southern Nigeria, where the fruit is called udala, it has become popular among adults, especially pregnant women, who believe it facilitates an easy birth. Today, this species’ broader potential is unexplored and the white star apple’s value in organized commercial plantings remains untried. It deserves better. An important feature is that its fruit comes available in the dry season, a time when all too often there is not enough to sell or eat. In parts of West Africa, seeds are occasionally collected and their oil extracted for soapmaking or cooking. Latex is also tapped from the trunk and used as rubber. The bark and tender leaves have medicinal applications. Local dancers use the hard, sharp, beanlike seeds in rattles. Easy to saw and plane, the brownish-white wood nails well, takes a fine polish, and is highly sought for construction work, tool handles, and much more. (Sapotaceae) as Central America’s chicle tree, the original source of chewing gum.

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STAR APPLES 321 African Star Apple This tall West and Central African tree (Chrysophyllum africanum A. DC or Chrysophyllum delevoyi De Wild.)5 is found from Sierra Leone to the Congo basin and Angola. Its fruits have an apricot color and a pleasant acid pulp that is much esteemed. Although children scavenging the hillsides grab most of them, enough surplus occurs that they are sold in both rural and urban markets and eaten with relish by many adults. Across most of its range there are no organized plantings. However, in villages in Benin and southern Nigeria the tree is apparently deliberately cultivated. Internationally, the species is known for its top-grade timber, marketed under the name longhi (or longui) rouge. Milkplum This small evergreen tree (Bequaertiodendron magalismontanum (Sond.) Heine & J.H. Hemsl.)6 is distributed widely, from Guinea to Tanzania and from Nigeria to South Africa, where it is one of the more popular “veld fruit.” Its bright scarlet, plumlike fruits have a pinkish-purple pulp of pleasant flavor. Women often collect large quantities, crush them in water, and boil the resulting extract with maize to produce a colorful and tasty porridge. The fruits are so relished that there are seldom enough on hand to meet the demand. Jam and jelly, not to mention vinegar, wine, brandy, and syrup, are also made. The jam—not unlike plum jam in appearance and flavor—is slightly, and deliciously, tart. It has been called “excellent.” The small tree, often hardly more than a shrub, is relatively drought- resistant and at least some types seem frost-hardy. It grows on many soils, but seems to occur most commonly on dry and well-drained slopes. In South Africa, for instance, it is found in ravines (kloofs) or small rocky hills (kopjies), notably in the Gauteng-KwaZulu-Natal region. The fruits cluster along the branches, hanging like small, bright-scarlet plums. Inside, they lack the segments and star-shaped arrangement of seeds. Instead, there is a single central seed. The fleshy pulp is rich in sugars and contains moderate amounts of vitamin C and minerals. Regardless of its food value, this species is promising for protecting and improving stressed sites. It could prove useful, for example, in land reclamation, erosion control, and especially wind erosion reduction. Its use as a fruit crop in orchards or mixed cropping systems is as yet unexplored, but that also seems to be a promising line of investigation. 5 The taxonomy of this species remains somewhat murky. Chrysophyllum africanum (C. delevoyi) is so similar to C. albidum that it may be just a variety of it. C. edule Hoyle may be another synonym. Common names include omumu, alasema, or odara pear. 6 Synonym are Chrysophyllum magalismontanum Sond and Englerophytum magalismontanum (Sond.) T.D.Penn. It is also called wild plum, stem fruit (stamvrug in Afrikaans), or red milkwood.

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LOST CROPS OF AFRICA 322 Although native to lowland tropical or subtropical climates, the tree is said to adapt to a wide range of environments and climatic conditions. Forest Milkplum This large tree (Chrysophyllum viridifolium J.M. Wood & Franks) is native to eastern South Africa (notably the Natal coast), Swaziland, and Mozambique. Its fruits are yellow and smooth with a yellowish-white pulp. They are shaped and sized like little apples, and are said to ripen irregularly throughout the year. Little else has been reported about them so far. Milkwood Found from the mountains bordering Zimbabwe, Mozambique, and Malawi as far north as the highlands of Cameroon, Uganda, and Kenya, this tall, stately montane-forest tree (Chrysophyllum gorungosanum Engl.) produces well-liked fruits. These large oval berries, usually containing four or five brown seeds and a milky pink flesh, have a pleasantly acid taste. They are said to make a splendid jam. Owing to the tree’s height most are now accessible only to birds, bats, and monkeys. However, the species might make a useful cultivated crop. In orchard production or village plantings horticultural manipulation such as pruning could be employed to control the height and produce a reachable harvest. Other edible-fruited African Chrysophyllum species, about which even less is known, include: Chrysophyllum lacourtianum De Wild. Large, yellow, acid-tasting fruits the size of oranges. Found in West Africa, producing good timber. Chrysophyllum natalense Sond. (Bequaertiodendron natalense (Sond.) Heine & J.H. Hemsl.) The red fruits have a tart but pleasant flavor and are much enjoyed by humans and animals alike. Found in South Africa (Natal coast). Chrysophyllum obovatum (Sabine & G. Don) Hemsl. Agreeable tasting fruits, the size of small apples. Found in Central Africa. Chrysophyllum pruniforme Pierre ex Engl. Known as forcados star apple or Gabon plum, this tree bears yellow fruits the size of tennis balls. Found across West and Central Africa, it can be found at least as far eastward as western Uganda.

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