Kids Research Express

Corn or Maize, common name for the cereal grass widely grown for food and livestock fodder. Corn ranks with wheat and rice as one of the world’s chief grain crops. The corn plant has an erect, solid stem, rather than the hollow one of most other grasses. It varies widely in height, some dwarf varieties being little more than 60 cm (2 ft) at maturity, whereas other types may reach heights of 6 m (20 ft) or more. The average is 2.4 m (8 ft). The leaves, which grow alternately, are long and narrow. The main stalk terminates in a staminate (male) inflorescence, or tassel. The tassel is made up of many small flowers termed spikelets, and each spikelet bears three small anthers, which produce the pollen grains, or male gametes. The pistillate (female) inflorescence or ear is a unique structure with up to 1,000 seeds borne on a hard core called the cob. The ear is enclosed in modified leaves called husks. The individual silk fibers that protrude from the tip of the ear are the elongated style

Wheat, common name for cereal grasses of a genus of the grass family, cultivated for food since prehistoric times by the peoples of the temperate zones and now the most important grain crop of those regions (see Agriculture ). Wheat is a tall, annual plant attaining an average height of 1.2 m (4 ft). The leaves, which resemble those of other grasses, appear early and are followed by slender stalks terminating in spikes, or so-called ears, of grain. CLASSIFICATION Species of wheat are classified according to the number of chromosomes found in the vegetative cell. They are divided into three series: the diploid, or einkorn, containing 14 chromosomes; the tetraploid, or emmer, containing 28 chromosomes; and the hexaploid, containing 42 chromosomes. Wheat species crossbreed relatively frequently in nature. Selection of the best varieties for domestication took place over many centuries in many regions. VARIETIES According to the regions in which they are grown, certain types of

Plum (tree), fruit tree of a genus of the rose family, which also contains the other trees that produce drupes (hard-pitted fruits): peach, cherry, almond, and apricot. About 12 plum species are cultivated throughout temperate regions for their fruit and as flowering ornamentals. The trees are rarely more than 10 m (33 ft) high. The plum varieties, which are suited to both warm and cool climates, exceed the other drupes. The common European plum, the most important species, has been cultivated since ancient times and probably originated near the Caspian Sea. It was introduced into North America, possibly by the Pilgrims, and is now mostly cultivated in the western United States. Fruits of varieties of this species range in color from yellow or red to green, but purplish-blue is most common. Dried plums, or prunes, are made from the varieties that are richest in sugar and solids. The Japanese plum, probably originating in China, was introduced into the United States in 1870. The fruit

Apple, common name for certain related trees of the rose family, and for the pome fruit of the trees. The apple tree, a deciduous plant, grows mainly in the temperate areas of the world. The fruit is a firm, fleshy structure derived from the receptacle of the flower. Apple leaves are broadly oval in shape and are somewhat woolly on the undersides. The flowers in bloom have a rounded appearance. Some apple blossoms are white, but the majority of apple blossoms have stripes or tints of rose. A few apple species bloom with bright red flowers. Apple wood is hard, durable, and very fine-grained. The physical characteristics of the fruit are subject to considerable variation. The skin color may range from green to a deep, blackish red. Shapes, also, are diverse and include oblate and oblong fruits and fruits of a size hardly larger than a cherry or as big as a medium-sized grapefruit. Scientific classification: Apple trees belong to the family Rosaceae. They constitute the genus Malus.

Mango, common name for a tree, and for its fruit. The tree, which is native to India, grows up to 15 m (50 ft) high, with spreading top and numerous branches. It is widely grown in the tropics for its succulent fruit. The fruit, which is a fleshy drupe, is somewhat kidney-shaped or oval, from 5 to 15 cm (2 to 6 in) in length; greenish, yellowish, or reddish in color; and contains a large flattened stone. Scientific classification: The mango belongs to the family Anacardiaceae. It is classified as Mangifera indica.

Peach, common name for a deciduous orchard tree of the rose family, and for the fruit of this tree. The tree, which botanists believe is native to China, is cultivated throughout warm temperate and subtropical regions of the world. In the peach fruit, the stone is covered with a fleshy substance that is juicy, melting, and of fine flavor when matured and mellowed. The peach tree is of moderate height, more or less spreading according to variety, and, when left to itself, deep-rooted. The popular division of fruit varieties into clingstones and freestones—referring to the relative tendency of the flesh to cling to the stone—is by no means accurate. These two classes merge in different varieties, and even the same variety may be freestone and clingstone in different seasons. The nearly 300 varieties of peaches grown in America have been classified into five races, each with outstanding characteristics, ripening season, and uses. The nectarine is a variety of peach. The peach is not a

Aloe, genus of plants with more than 150 species, most native to South Africa. They usually have short stems, fleshy, lanceolate leaves crowded in rosettes at the end of the stem, and red or yellow tubular flowers in dense clusters. Species vary in height from several centimeters to more than 9 m (30 ft); they are widely cultivated as garden and tub plants. Several species are commercially important as the source of the aloes used in medicine. Scientific classification: Aloes belong to the family Liliaceae.

Agave, genus of plants native to desert regions of the western hemisphere. The best-known species is the American aloe, or century plant, which usually flowers only once, between the ages of 10 and 25 years. Shortly before it flowers, a long stalk grows rapidly upward to a height of about 12 m (about 40 ft). The flowers are large and greenish and cover short, horizontal branches that spring from the upper half of the stalk. Some plants die after flowering, but rhizomes of suckers often develop into new plants. The plant may also be grown from seeds, bulbs, or underground stems. The agave has large, thick, and fleshy leaves, which can store considerable quantities of water. They are spiked, particularly at the tips, are evergreen, and grow to a length of about 2 m (about 6 ft) in a cluster around the base of the plant. Many species of agave are of economic importance. Sisal, native to the West Indies but now also grown in Mexico and various tropical countries of Eurasia, yields sisal or

Succulent, in botany , a tropical or desert plant with thick and fleshy stem or leaves designed to retain water and minimize evaporation. Succulent plants are usually found in regions of little rainfall and generally have long roots to absorb a maximum amount of water. Some of the commonest succulents are the cactus , which are leafless or have short, prickly leaves, storing a lot of sap in the stem; and the agave and aloe , which collect water in the stem.

Protoplasm, term once used to describe the ground substance—the living material—of cells. This material would include the complex colloidal organization of substances making up a cell's nucleus, cytoplasm, plastids, and mitochondria. The term protoplasm has to a great extent been replaced by the term cytoplasm; the latter, however, does not include the cell nucleus. Protoplasm is also used to describe the contents of the tubelike structures (hyphae) of which fungi are composed.

Ergot, name used interchangeably for a disease of rye, for the fungus causing the disease, for the sclerotium (compact hardened mycelium, or fruiting surface) of the fungus, and for the dried sclerotium, which contains certain valuable drugs. Ergot fungi are molds that infect rye and other cereals and wild grasses. The filamentous mycelium of the mold spreads through the tissues of the flower and attacks the ovaries, which become deformed and enlarged and then wither. The deeper mycelium within the ovary becomes dense and hard, forming sclerotium. The dried sclerotium as used in medicine contains the crystalline alkaloids ergotamine, C33H35N5O5, and ergotinine, C35H39N5O5, and the amorphous alkaloid ergotoxine, C35H39N5O5. Histamine is also present in minute quantities. In moderate doses ergotamine causes the contraction of unstriped muscle fibers, such as those in terminal arterioles. It is used to control hemorrhage and to promote contraction of the uterus during childbirth; it

Mushroom, technically confined to members of a family of fungi with gills, but in popular usage any of the larger fleshy or woody fungi. The application of the term mushroom to edible species only and the term toadstool to those considered poisonous or otherwise objectionable has no scientific basis. For example, two poisonous fungi may be less closely related than are a poisonous species and an edible one. Of the thousands of species of mushrooms known throughout the world, the great majority are tough, woody, bitter, tasteless, or of such rare occurrence that they are of no interest as food. A few species produce death or serious illness when eaten. No simple rule exists for distinguishing edible and poisonous mushrooms, but the characteristics of the more common edible species can be readily learned, and collecting activities should be confined to such species. Morels, puffballs, and other species described below are not ordinarily confused with dangerous types; whenever doubt aris