This site is for general and professional educational purposes
Information on the basics of Economic Botany
Legumes, Nuts & Seeds
Please CLICK on Underlined Categories to view:
[ to search for Subject Matter, depress Ctrl/F ]:
Legumes rank next in importance to cereals as human food sources. They contain more protein than any other vegetable and thus are akin to animal meat in food value. Fats and carbohydrates are also present. The proteins occur as small granules in the same cells with the starch grains. The high protein content is related to the presence on the roots of many legumes tubercles that hold nitrogen-fixing bacteria. These bacteria are able to convert atmospheric nitrogen into nitrates. This augments the nitrogenous material available for the plants.
The legumes belong to the family Leguminosae, which is noted for having a special kind of fruit, a legume, which is a pod that opens along two sutures when the seeds are ripe. Over 11,000 species of legumes are known, and many are of importance as industrial, medicinal or food plants. They have been cultivated and used for food for centuries worldwide. The seeds are of greatest importance. As is the case with other dry seeds, the low water content and impervious seed coats enhance their value for long-term storage and increase their longevity. Legumes are easy to grow, they mature rapidly and they are highly nutritious. Not only are proteins abundant but also they possess minerals and vitamin B. They are absolutely essential in a vegetarian diet. Before the discovery of potatoes, they constituted a greater part of the food in Europe. Legumes have a high-energy content and are particularly well suited for use in cold weather or where physical exertion is pronounced. The immature fruits also serve as food as demonstrated by garden beans and peas.
Because all parts of the plant are rich in protein, legumes are valuable as field and forage crops. When plowed under they are an excellent fertilizer and greatly increase the nitrogenous content of soil.
The common pea, Pisum sativum, is native to Southern Europe and has been cultivated since before the Christian era. Peas were well known to the Romans and Greeks. However, it wasn’t until the middle of the 17th Century that production became more widespread in Europe. The earliest colonists brought peas to America. Peas are annual, glaucous; tendril bearing, climbing or trailing plants, with white or colored flowers and pendulous pods. Although originating in warm regions they thrive where there is a cool summer and abundant moisture.
The gray pea of Greece and the Levant is thought to have given rise to Field Peas. They have colored flowers and angular colored seeds and are very hardy, withstanding frost and altitudes up to 8,000 ft. Field peas are grown for seed that is used for human consumption in the form of pea meal or split peas. They are also an excellent grain for livestock. The plants are sued for forage, silage and green manuring.
Garden peas have white flowers and round smooth or wrinkled seeds that are yellow or white in color. They contain more sugar than field peas and the seeds are eaten green or are used for canning. For canning peas are usually harvested with a mowing machine. Pea-cannery refuse is a valuable livestock feed. In some varieties the pods are fleshy and crisp and are consumed as well as the seeds. Garden peas wee used by Gregor Mendel in his experiments in plant genetics.
Chickpeas (Garbanzo Beans)
Chickpeas, Cicer arietinum, are native to southern Europe where they are still extensively grown. They are an important food in many parts of Africa, Asia and Central America. India has grown an amount that is equal to the sugar cane acreage of the whole world. The plant is a branching, bushy annual, which mature in 90 days. It is well adapted to arid and semiarid regions. Chickpeas are the best legumes for human consumption as the seeds are very nutritious. The early Egyptians, Hebrews and Greeks grew them. The sparse foliage is poisonous so the plant cannot be used for forage. The green pods are infrequently consumed and the seeds are used as a substitute for and as an adulterant of coffee.
Cowpeas, Vigna sinensis, are more closely related to beans than to peas. They are vigorous bushy or trailing summer annuals with curious, cylindrical pendant pods. The plant continues to grow if environmental conditions are suitable. The cowpea is a very old crop, probably originating in Central Asia, although it has been grown in Southeastern Asia for over 2,000 years. It was introduced into the tropics and subtropics of the world, reaching the West Indies in the 17th Century and North America in the 18th Century. The seeds are used as feed for poultry and cattle, and they may serve as a coffee substitute. The main value is as a forage crop, as a cover crop to prevent erosion and as a green manure. Cowpeas are important in India, China and the southern United States. It is susceptible to frost and is confined to warm humid areas in a sandy or loamy soil.
This is a pigeon pea, Cajanus cajan, that was first domesticated in Asia or Africa and is now widely cultivated in the tropics and subtropics, especially in the East Indies, the West Indies and India. There are many varieties. The plant is an erect shrub. Both the immature and mature seeds have been used for human and animal food for thousands of years. In modern times it has been developed as a forage crop and rivals alfalfa in importance. It is drought resistant, grows well in any kind of soil, matures rapidly and in other ways is highly desirable.
Garden or kidney beans, Phaseolus vulgaris, are indigenous to America. They were probably domesticated by the Incas and were early used by the Amerindians of both South and North America. In modern times the young pods (string or snap beans), the unripe seeds (shell beans) and the dried ripe seeds are all used for human consumption. The whole plant is used for forage. Beans are low, erect or twining annuals with small white or colored flowers, trifoliate leaves and slender pods. They are grown as either bush or pole beans and over 1,000 varieties are cultivated. Both groups have green-podded and wax-podded varieties. The commercial dried bean is of more recent origin. It was first grown in 1836 in New York state. Much of the bean crop is canned. Even though beans will grow on a variety of soils, a fertile soil, rich in lime, is required for a good yield. A warmer climate than for peas is desirable, and crop rotation should be practiced. On large farms machines harvest the crop and the beans are dried, stored and threshed before marketing. The culls are fed to livestock and the straw is used for forage. Presently these beans are grown worldwide.
Lima beans, Phaseolus limensis, are native to Peru and Brazil and have been grown in South America for centuries. Originally a perennial they are usually treated as annuals. Lima beans require warmer weather and higher humidity than Garden Beans. The original types were pole beans, the bush limas arising later as mutations. Either green or dried beans are consumed and a large quantity is processed. In addition to the large variety there is a smaller form, the Sieva Bean (Phaseolus lunatus), also native to tropical America.
Other species of Phaseolus that are often cultivated include the Scarlet Runner Beans, P. coccineus that have a thickened root and ornamental flowers and the Mung Bean, P. aureus. Mung beans were grown in India in ancient times and are still an important crop. The small oval seeds are highly nutritious and the green pods are also consumed. There are over 100 varieties grown in China and other parts of Asia. The Mung Bean is grown in North America principally as a forage plant. The Adsuki Bean, P. angularis, is next to the Mung Bean in importance in Manchuria and China; and the Rice Bean, P. calcaratus, is widely cultivated in Southern Asia.
Soybeans, Glycine max, are small, bushy, erect or prostrate annual plants that resemble the cowpea. The crop is much easier to handle for it does not become tangled, matures earlier and has a higher yield, produces a better seed and can be threshed. The seeds all mature at the same time. The soybean is one of the oldest cultivated crops. It was grown in China centuries before the first written records in 2,838 B.C. It is indigenous to Southeastern Asia, where over 1,000 varieties are grown. Manchuria has led commercial production, followed by Korea, Japan, China, Indonesia and North & South America. Soybean is the most important legume in Asia there it is consumed fresh, fermented or dried and is used everywhere in the daily diet to supplement rice. The seed is the richest natural vegetable food known. In tropical areas, especially Indonesia, soybeans are boiled and then fermented by addition of a mold to yield a food known as Tempe. Soybean sauce, made from cooked beans, roasted wheat flour, salt and ferment, is widely used. The flour, with a low carbohydrate and high protein content, is an excellent food for diabetics. Soybean milk, extracted from the seed, is used in cooking and is used as a substitute for cow’s milk. Soybean sprouts are a favorite food in the Asian diet.
The soybean has ever increasing other uses worldwide. It is an important aid to agriculture, a valuable commercial crop, a good livestock food and the source of numerous raw materials for use in industry. Soybean oil is an important drying oil. Soybean protein is extensively used to produce the foam liquid used for extinguishing oil fires and as the source of a synthetic fiber, similar to casein fibers.
Ever since the 1930’s soybean has assumed a position of great importance in the agriculture of the United States. It is of greatest importance in the North Central states, with Illinois producing over 50 percent of the total crop. Soybeans are grown for hay, silage, and green manure, as well as for the seeds, and hundreds of varieties are known. It can be grown under a variety of soil and moisture conditions but requires a rather warm temperature and is susceptible to frost.
Broad Bean, Vicia faba, is also called the Windsor Bean, Horse Bean or Scotch Bean. It is grown as a forage crop as well as for the seeds that furnish food for both humans and livestock. The plant is a strong erect annual, 2-4 feet tall, with flat pods and large seeds. It was cultivated in prehistoric times and most likely is indigenous to Southwestern Asia or Algeria. Over 100 varieties have been grown, mainly in the Old World. The broad bean was the only edible bean known in Europe before the voyages of Columbus to America. It is an important crop in England. Its growth is encumbered by dry hot summers and thus is not a preferred crop in most of the United States. It is sometimes used as a cover crop, in crop rotation and for livestock fodder and silage as well as for the seeds.
Horse or Jack Beans, Canavalia ensiformis, are indigenous in the West Indies and are now grown in almost all tropical countries for their seeds. The plants are bushy annuals with long sword-shaped pods that may contain as many as 12 large beans. The unripe seeds and pods are used for human food and the whole plant serves for green forage. The plants are hardy, drought-resistant and immune to most pests. They are grown principally in the southern United States.
Velvet beans, Stizolobium deeringianum, are widely cultivated in the tropics for their edible seeds and for fodder. The plant is an annual herbaceous climber that exceeds most other legumes in the rapidity and extent of growth. It has become of some importance in the Southeastern United States.
Peanuts, or Groundnuts, Arachis hypogaea, are true legumes rather than nuts because the shuck is merely a shell-like pod. The plant is a bushy or creeping annual with the strange habit of ripening the fruit underground. The peanut is indigenous in South America but was early carried to the Old World tropics by the Portuguese explorers and is now grown extensively in most tropical countries. It was brought to Virginia from Africa and is now one of the most important crops in the Southeastern United States. There are over 20 different kinds of peanuts grown that differ in habit and the size of the pod. The cultivation of peanuts is quite complex. They require ample warm sunshine and a moderate rainfall and can be grown successfully only south of 36 deg. North latitude. A sandy soil is preferred, although any but a low soil can be used. The soil must be friable so that the ripening fruit can be buried and it must be well fertilized. During harvest the rows are plowed and the plants are lifted out with forks, shocked and capped for cure. Later the fruits are removed, cleaned and polished. The plants may be used for forage, livestock feed or as soil renovators. The nuts or seeds are used for roasting or salting. In candy and for the preparation of peanut butter. For the latter the seed coats and embryo are removed and the nuts are roasted either dry or in oil, and are then ground to a paste. Peanuts are very nutritious. One pound yields 2,700 calories whereas one pound of beef furnishes only 900 calories. Nevertheless, some are allergic to peanuts and must take precautions to avoid ingesting peanuts or their derivatives. Peanut oil is important food oil. The oil cake is fed to livestock. The protein contained in the nuts has been used in the manufacture of Ardil, a synthetic fiber.
Lentils, Lens culinaris, are some of the most ancient of foods and also one of the most nutritious. The ancestral home is Southwestern Asia, but they were introduced into ancient Egypt and Greece. Lentils are often mentioned in the Bible. The plant is a slender, tufted, many-branched annual with tendrils. The pods are short and broad, with small lens-shaped seeds. The seeds are used principally in soups and in East Indian cuisine mixed with rice and herbs. They are easy to digest, more so than meat. These are produced in colors that vary from gray to tan and red. The plants have been used for fodder.
Lablab, Dolichos lablab, is a bean-like legume that is grown in many tropical areas. The plant is usually a woody climber with a high yield of pods that continue to bear over several years, but that may also be grown as an annual. Both the pods and the seeds are consumed, and the entire plant is used for hay and forage for horses and cattle.
The need for forage crops arose with the domestication of animals. Initially wild grasses probably were used, but other sources were then sought. These gradually became more numerous and more varied. Today the extensive cultivation of grasses and legumes as forage crops is principally the product of European and American civilizations. In addition to various cereal grasses and food legumes, many other species have been grown entirely as forage crops with little or no value as human food. Included are such grasses as Timothy, Phleum pratense, Orchard Grass, Dactylis glomerata, Redtop, Agrostis alba, Brom Grass, Bromus inermis, Johnson Grass, Sorghum halepense, Tunis Grass, Sorghum virgatum, and Sudan Grass, Sorghum vulgare var. sudanense.
Alfalfa, Medicago sativa, native to Southwestern Asia, may have been the first cultivated forage plant. it was known to the Greeks, Romans and Persians. It was introduced into China and Europe and reached North America during the European colonization. Alfalfa has become the most important forage crop grown in the United States and many new varieties were developed. It is especially abundant in Middle Western and Western states. Alfalfa is useful for pasture, hay and silage and for improving the soil. Dehydrated alfalfa or alfalfa mean is also used, and alfalfa sprouts are used for human food. Other species of Medicago include Bur Clover, M. hispida and Medic, M. lupulina.
Clover, Trifolium spp., is grown particularly in the Northeastern and North Central united States. It is valuable in crop rotation and is often grown in mixtures with forage grasses. Important species are Red Clover, Trifolium pratense, Alsike Clover, T. hybridum, Ladino or White Clover, T. repens, and Crimson Clover, T. incarnatum.
Sweet clovers, Melilotus spp., have become important forage crops since the beginning of the 20th Century. They are especially valuable for pastures and for soil improvement. Most production is centered in the Corn Belt of the United States. Both White Sweet Clover, Melilotus alba, and Yellow Sweet Clover, M. officinalis, are grown.
Kudzu Bean, Pueraria lobata, is a drought-tolerant perennial legume indigenous to Japan and Eastern Asia. It was introduced into the Southeastern United States in the middle 20th Century. The plant has a long tap root and produces runners of 50-100 feet in length. Kudzu yields good hay and forage and was important in erosion control. The pods can be used and a valuable starch is obtained form the large roots. Gradually kudzu escaped into the countryside and has begun to smother native vegetation. By the 21st Century it had attained a pest status of very grave concern as few efforts to eradicate it or to reduce its abundance have succeeded.
Three species of Lespedeza of some importance in the Southeastern United States are the annual Common Lespedeza, Lespedeza striata, a Korean species, L. stipulacea and a perennial from China, L. cuneata. These are beneficial to soil conservation and for renewing exhausted soils. They furnish excellent hay and pasturage.
There are a number of Vicia spp, both native and introduced, that are used for forage, especially in the coastal areas of the United States. Two species of importance are Common Vetch, Vicia sativa, and Hairy Vetch, V. villosa. They are mostly weak-stemmed, viny annuals that are useful for cover, green manure and soil improvement as well as for hay, pasture and silage. Livestock find them very palatable. They are frequently grown in mixture with small cereal grains.
Tree legumes have come into prominence as replacements for cereal grasses on eroded soils. A few species are excellent substitutes for maize, wheat and other cereals in livestock feeding. Some of the more important tree legumes are the following:
Mesquite, also known as Algaroba and Keawe, Prosopis juliflora, is native to the West Indies, Central America and Mexico. The introduction of a single tree into Hawaii was followed by a spread to the drier climatic zones of all the islands. It is considered a desirable species on the islands. The flowers are a source of honey and the pods and ground seeds are important livestock feed. Mesquite gives an enormous yield of 2-10 tons per acre depending on the local rainfall. It has been estimated that one acre of mesquite can produce 1,600 lbs. of beef, while one acre of corn or alfalfa produces only 450 lbs. Mesquite trees grow rapidly, are drought-tolerant and can utilize arid, barren ground where other crops will not grow. Cultivation of Mesquite has extended to other parts of the world with similar climate. Another species, Prosopis glandulosa, is better adapted to colder climates.
The carob tree, Ceratonia siliqua, is native to Syria but has been cultivated since ancient times in other Mediterranean countries. Carob was the “locusts” that were the food of John the Baptist and the Prodigal Son of the Bible (Hill 1952). The large pods have served as livestock feed for ages. The tree is a small evergreen with glossy green foliage. It blooms in autumn and carries the young fruit until late the following summer. It does best in rocky dry soil. Carob trees give a very high yield of pods. These contain 50 percent sugar and are often consumed directly in the dried state. The ground seeds yield a highly nutritious meal that can be added to bread. The pods contain a valuable gum known as Tragasol. Although a handsome tree, the bloom gives an obnoxious odor and the numerous pods falling to the ground are a messy problem in the urban setting.
Honey locust, Gleditsia triacanthos, is indigenous to the humid eastern North America in areas of hot summers and cold winters. The pods contain 29 percent sugar and are readily eaten by livestock. Honey locust is also a valuable ornamental and timber tree.
Many other tree legumes are of some importance in world argriculture. There is another mesquite, Prosopis glandulosa, a spiny shrub of the arid southwestern deserts of North America. It has pulpy pods that have long served as food for humans and livestock. The Rain Tree, Samanea saman, a huge tropical American tree, bears curved black pods that are filled with sweet pulp and which is an excellent livestock feed. The Nittas, Parkia biglobosa and P. filicoidea, of West Africa have large pods with 31 percent sugar content. The seeds yield a very nutritious flour with 36 percent protein, 23 percent fat, 15 percent starch and over 12 percent sugar. They are widely used by the natives when traveling as they constitute a concentrated natural ration. In other parts of tropical America Inga edulis and other species of the genus are cultivated for their pods, which have a sweet and agreeable pulp, and as shade trees in coffee plantations.
The term “nut” is used loosely to describe a number of related or unrelated plant structures. Officially a nut is a one-celled, one-seeded dry fruit with a hard pericarp or shell. Some of the so-called nuts of commerce correspond to this description. Among them are the acorn, filbert, chestnut and hazelnut. The others may be seeds, as the Brazil nut; legumes, such as the peanut; or dry drupes from which the outer parts of the fruit have been removed, such as the almond, coconut, pecan and walnut. The following discussion will group all of these together regardless of their morphological nature. They will be classified according to their fat, protein and carbohydrate contents.
The Brazil-nut tree, Bertholletia excelsa, is a giant with a rough bark in the Amazon forests in South America. It bears 18-24 hard, brown, spherical, woody fruits from 4-6 inches in diameter and weighing 2-4 pounds. Each fruit contains 12-24 seeds with a hard bony covering. These are the Brazil nuts of commerce, also called Cream Nuts. They have served as human food for centuries. The food value is very high with a fat content of 65-70 percent and protein content of 17 percent. Collection and shipping of these nuts is an important industry in South America. Trees are rarely cultivated and most of the output is obtained from the wild trees. There are also similar nuts of finer quality and more delicate flavor obtained from the Sapucaia or Paradise-nut trees, Lecythis usitata, Zabucajo sp., and other species.
The cashew nut tree, Anacardium occidentale, is a handsome native of Brazil that is now extensively cultivated in tropical countries from Mexico to Peru and Brazil, in the West Indies, southern Florida and the Mediterranean area, Mozambique, India, and the East Indies. It bears a thin-skinned, pear-shaped, yellow or reddish, juicy “fruit” known as the Cashew Apple. This is actually the swollen peduncle and disk. The true fruit, a small curved or kidney-shaped structure, is borne on the outside of the “apple” at the distal end. This is the cashew “nut.” The rich kernel is delicately flavored and contains nutritious oil. The grayish-brown coat, or shell, contains oil that blisters the skin. The ripe fruit, which as a characteristic aroma, is consumed in many countries or used for preserves. The fermented juice makes a wine, Kaju that is sometimes bottled. The leaves, the light close-grained wood, the sap and the bark are also useful.
This is one of the most important economic plants especially in the South Pacific and other tropical areas. Coconut is a palm, Cocos nucifera, probably native to the Malay archipelago, but possibly of Ecuadorian and Central American origin. It grows best near the seashore, but can occur at altitudes of 5,000 ft. It is undoubtedly one of the most graceful and beautiful of all palms, often with a typical leaning habit. The bases of the slender trunks are swollen. The large pinnate leaves are 6-12 ft. long and 18 in. wide. They are borne in a cluster at the top of the stem. The flowers are formed in a large compound spadix, enclosed by a spathe. The fruit is a 3-sided dry drupe. It consists of a smooth rind, or exocarp; a reddish-brown fibrous mesocarp; and a hard stony endocarp, or shell that encloses the seed. The white meat and milk represent the endosperm of the seed; the embryo is embedded in the hard endosperm.
The coconut plants have many uses. The leaves are highly incendiary that when burned produce a bed of coals which imparts a delicious flavor to grilled meats. The fibrous husk yields Coir, a textile fiber. The hard shell, or endocarp, is used for fuel, vessels and other containers, and a fine grade of charcoal. The water of the green coconut makes an agreeable and refreshing drink. The meat may be eaten raw or shredded and dried to form desiccated coconut. It is frequently ground and pressed through a cloth after water has been added. The resulting coconut milk is very palatable and a good substitute for cow’s milk as it contains several vitamins. However, the main use of the meat is for copra, the source of coconut oil and oil cake. The unopened inflorescences yield a sweet liquid that is converted into palm sugar or fermented to make palm wine, arrack, or vinegar. The leaves are also used for thatching, baskets, hats, mats and curtains. The petioles and midribs are used for fence posts, canes, brooms, needles and pins. The trunk furnishes a strong, durable wood for houses and bridges. Some of the porcupine wood of commerce, much used for cabinetwork, is from the coconut. The heart of bud at the apex of the stem is used in salads or is cooked. The bark contains a resin and the roots a drug.
Coconuts thrive best within the true tropics, but they will grow at higher latitudes. They grow best in fertile soils. Wild trees are an important source of coconuts, but commercial plantations abound. Mature nuts are planted in a nursery and barely covered. They germinate in a few months and the seedlings are transplanted when about a year old. Proper spacing, clean cultivation and intercropping improve growth. Cover crops, fertilization and irrigation also help to maintain the yield. Flowering and fruiting at tropical latitudes are continuous and ripe nuts can be obtained during every month of the year. Harvest is usually every two months. The yield and size of the nuts vary with the spacing and the variety planted. About 3,000-7,000 nuts are required to produce one ton of copra, which yields 1,200 lbs. of coconut oil and 800 lbs. of oil cake. One thousand nuts can yield 165 lbs. of coir fiber. Great care must be taken not to lie beneath the trees, as the fruit is very heavy and can cause grave injury when falling.
Driving them against a sharp spike fastened to a piece of wood and wrenching them apart husk the coconuts. An experienced person can husk 1,200-2,500 nuts per day. The nuts are broken into two halves with a blow of a heavy dull knife. The dried meat or copra, the most important product, is prepared in different ways. About half the supply is dried by simple methods, using the sun or drying on racks over fires made from coconut shells. After a few days the meat curls away from the shell and can readily be detached. Copra prepared in this way is dark colored and has an oil content of about 50 percent. Plantation copra is dried within 24 hours in the sun followed by heat from fires in drying houses. This copra is white and has a high oil content (60-65 percent). The best grade of copra has traditionally come from Sri Lanka.
Desiccated coconut is used by confectionery and candy makers and in cooking. It is prepared from the best grade of nuts. These are cured for several weeks and then carefully cracked and the meat is removed while fresh. This is washed and cut into threads and dried in a vacuum for one hour at 160 deg. Fahrenheit.
Hazelnuts, Corylus spp., are found in cool temperate regions of both hemispheres. The native American shrubs, Corylus americana and C. cornuta, produce small nutritious and palatable nuts of no commercial importance. Larger European species, C. avellana and C. maxima, are the source of Filberts, Cob Nuts and Barcelona Nuts. Filberts are cultivated in Southern Europe and Oregon.
Hickories, Carya spp., are native American trees common throughout the eastern deciduous forest. Butternut hickories contain a large amount of tannin and are not suitable for food but are eaten by livestock. Another group has sweetish edible nuts, the best of these being the Shagbark Hickory, Carya ovata and Shellbark Hickory, Carya laciniosa. These can be some of the finest of the wild nuts in North America and they have excellent storage qualities. The trees show promise under selection and experimentation. They can be grafted and crossed and many new varieties adapted to a wide range of soil and climatic conditions have been produced. The nuts yield a fine salad oil and the wood is a valuable timber. The bark, which frequently sloughs off, is used in smoking meats.
Macadamia trees, Macadamia ternifolia, are native to northeastern Australia. They produce a nut also known as Queensland Nuts. The tree has been introduced into other subtropical areas of both hemispheres. It has become of considerable commercial importance in Hawaii. Both thin-shelled and thick-shelled varieties are grown. The kernels have a sweet flavor that is enhanced by roasting and a rich oil.
The Pecan Tree, Carya illinoensis, is indigenous to the southeastern United States and northeastern Mexico. It is in the same genus as Hickory. The trees are extensively cultivated in both the Southern states and points west all the way to California, in the latter under irrigation. New varieties have extended the production northward into the upper Mississippi valley, Indiana and Virginia. Harvesting begins when trees are only 3-4 years of age. Paper-shelled varieties have been developed from East Texas stock. Pecans have a high fat content of 70% and they are used in desserts, candy, ice cream, cakes, etc. Pralines, consisting of brown sugar, vinegar and nuts, are a favorite confection in the South. Pecan pie is a delicious blend of nuts with a brown sugar custard base. Pecan oil and tannin obtained from the shells are by-products.
The seeds of Canarium ovatum, a native tree of the Philippines are Pili Nuts. They are very similar to Java almonds from C. commune of Eastern Asia and the East Indies. The seeds of both are consumed raw or after roasting. They have a spindle shape with a very thick hard shell. Fatty oil is expressed from the seed and used for human consumption and in oil lamps, and a resin is extracted from the tree. The plum-like fruit of the Pili is also edible.
Pine nuts or Piñons are obtained from the seeds of several species of Pinus, native to Western North America. Included are the Nut Pines, P. cembroides var. edulis and P. edulis var. monophylla; the Digger Pine, P. sabiniana; and the Torrey Pine, P. torreyana. These bean-sized nuts have a thin brownish-red shell and a slightly resinous flavor. Amerindians have always harvested piñons. The pinecones are harvested before they would open naturally. They are then roasted so that the scales will fall apart, which allows the seeds to separate. Wild birds and rodents quickly gather them when they open naturally in nature. The production is entirely from wild trees.
Pignolia Nuts are the seed of Pinus pinea of Southern Europe. These are longer and more yellow than piñons and have a rich delicious taste. Other species of pine provide edible nuts in India and Eastern Asia. China has increased its export of such nuts in the latter 20th Century.
Walnut trees provide both nuts and timber. They are native trees of North America and Europe.
Black Walnut, Juglans nigra, is an abundant tree of the eastern deciduous forest region of North America. It is a tall handsome tree that is often used for ornamental purposes. The large spherical fruits are green when ripe and the outer covering has to disintegrate or be physically removed to free the nuts. The walnut kernels have high oil content and were a favorite food of Amerindians. They retain their flavor when cooked and have a food value four times as great as meat. They are very difficult to crack and the husk stains the hands a dark brown so their wild harvest today is restricted to the very dedicated. These nuts are used mainly in the candy and ice cream industries. The tree is very productive and can be grown in a variety of soils and climates. Walnuts provide a valuable timber and also a brownish-black dye that was used by early settlers to dye hair.
Butternut, Juglans cinerea, is native to area with limestone soil in eastern North America. The tree is smaller than Black Walnut with elliptical nuts that have a deeply corrugated shell. Butternuts are high in fat content and are often preferred to walnuts because of their finer and richer flavor. The kernels are more readily separated. Sugar is sometimes obtained from the sap. They have often been used in the candy industry.
English Walnut, Juglans regia, [<Photos>] is indigenous to Iran and is widely cultivated in Southern Europe, China and other parts of Asia. In North America California and Oregon are leading producers. English walnut has been under cultivation for ages and many varieties exist. The attractive trees are usually planted in rows. Only the outer limbs produce perfect nuts. The kernels are easily freed from the pericarps and are bleached and polished. The furrowed kernels are the cotyledons of the seed, no endosperm being present. Walnuts yield excellent oil and the oil cake is a good livestock feed. The codling moth, Carpocapsa pomonella and Navel Orangeworm, Amyelois transitella, often attack the crop in North America and biological agents (parasitic insects) have been partially successful in control.
Almonds are probably the most popular of the high protein nuts. They are obtained from a medium-sized tree, Prunus amygdalus that is related to the peach and closely resembles it in blossoms and young fruit. Almond trees are also cultivated as ornamentals. The almond fruit is an edible drupe, with a tough fibrous rind surrounding the stone or “shell” and the seed or “nut.” There are two major types of almonds.
Sweet Almonds, Prunus amygdalus var. dulcis, have an edible seed and are the main source of the commercial product. The tree is native to the eastern Mediterranean where it has been cultivated for centuries. It is grown throughout Southern Europe and in California, Australia and South Africa. The seeds are especially delicious when eaten green. However, they are usually roasted or salted or made into a paste to be used for cake and bread. An extract is also prepared for flavoring. There are many varieties, some with think shells and some with hard shells. Jordan almonds are hard-shelled with a thinner integument on the seed and a finer flavor. In California a successful biological control effort against the Navel Orangeworm, Amyelois transitella, reduced harvest losses to below four percent.
Bitter Almonds, Prunus amygdalus var. amara, possess a bitter glucoside, Amygdalin that readily breaks down into prussic acid and thus prevents their use as food. Nevertheless, they are grown in Southern Europe as a source of the oil. During the extraction process the prussic acid is eliminated and the oil can then be used for flavoring. Bitter almonds are also used as a rootstock for sweet almonds.
The beech tree, Fagus grandifolia, is abundant in the eastern deciduous forest of North America. The high protein nuts are small, triangular and very sweet. They are of minor importance for human food, but are eagerly sought after by cattle, pigs, squirrels, poultry and other birds. They impart a fine flavor to pork, and razorback hogs are fed on the mast, which is a mixture of beechnuts, chestnuts and acorns. The European beech, Fagus sylvatica, yields slightly larger nuts that are consumed by humans and used for the edible oil of beechnuts.
Pistachio, Pistacia vera, also known as Green Almond, is a small tree indigenous to Western Asia. It has been cultivated in the Mediterranean region since before 2,000 B.C. It is now grown in Iran, Afghanistan, the southern United States and irrigated areas of the West, especially California. The fruit is a drupe. The seed contain two large green cotyledons with a reddish covering. These high protein “nuts” are salted in brine while still in the shell. They are highly prized for their color and resinous flavor and are combined with other nuts as mixed nuts and as a flavoring material for ice cream and candy. Their quality varies with the kind of culture. Restricting water reduces yield be improves flavor.
Acorns are the fruits of oak trees, Quercus spp. They are true nuts. Acorns have been used in America for fattening livestock, especially hogs. They are an excellent human food, but are rarely used except by indigenous people. The white oak, Quercus alba, and the live oak, Q. virginiana, are the best of the twelve or more species with edible fruit. The Amerindians have always used acorn flour. They ground the nuts, leached them to remove the tannin and other bitter qualities, pounded them into a meal and used them in porridge, mush and other ways. Acorns have been used in other areas of the world, for example they once furnished 25 percent of the food of the poorer classes in Italy and Spain in the form of acorn bread or cake. This is highly nutritious and may be stored indefinitely. Any species of acorn is edible after the tannin has been removed, but the holm oak, Q. ilex, is the main source. Oak trees are very productive and adapted to poor soil. The problem with acceptance of this food is its unaccustomed flavor, which is probably related to few persons being able to prepare it properly.
<bot120> Southern Live Oak, Quercus virginiana., South Texas
<bot243>Jeffrey Pine (Pinus jeffreyi ) & California Black Oak (Quercus kelloggii), San
Bernardino Mts., California
<bot301> Canyon Live Oak (Quercus chrysolepis), Palomar Mts., California
<bot375> California Black Oak (Quercus kelloggii), San Bernardino Mts., California
Chestnuts, Castanea spp., are found in the eastern United States, Japan and Europe. The American species, Castanea dentata, was once very abundant in the deciduous forest region. It was a handsome tree and furnished valuable timber as well as excellent quality nuts. These served as food, either raw or roasted, for over 200 years. Chestnut blight disease has about eradicated this tree from America, with no fruiting observed since the middle of the 20th Century. The European chestnut, C. sativa, with larger fruits has been extensively cultivated in Southern Europe for centuries and hundreds of varieties have been established. The nuts or marrons as they are called, are a standard food and are as important as wheat maize in America. They are grown everywhere, often on dry hillsides that are unfit for other purposes. The nuts are consumed raw or are roasted, boiled or used for stuffing or flour. The Japanese chestnut, C. crenata, is immune to chestnut blight and has been introduced into America. The nuts are often cooked like potatoes.
<bot735> American Chestnut (Bombacopsis glabra A. Robyns) (roasted seeds) [Neotropics]
<bot841> European Chestnut (Castanea sativa) (roasted fruit) [Europe]
Other Crops Where Seeds are Used
<bot754> Black Apple (Diospyros digyna Jacq.) (seeds; wood products) [Cent. America - West Indies]
<bot824> Cocoa (Theobroma cacao L.) (fruit & processed seed) [Central - Northern South America]
<bot743> Cocoplum (Fat Pork) (Chrysobalanus icaco L.) (fruit & roasted seeds) [Mexico-West Indies]
<bot759> Durian (Durio zibethinus Murr.) (fruit & roasted seeds) [SE Asia]
<bot741> Moreton Bay Chestnut (Black Bean) (Castanospernum australe A. Cunningham & Fraser)
(wood products; seeds boiled) [NE Australia]
<bot124> Opuntia sp. & Palo Verde (Parkinsonia aculeata ), South Texas
<bot705> Winged bean (Psophocarpus tetragonolobus ) [New Guinea]