The pear is classified within Maloideae, a subfamily within Rosaceae. The apple (Malus ×domestica) which it resembles in floral structure, is also a member of this subfamily. In both cases the so-called fruit is composed of the receptacle or upper end of the flower-stalk (the so-called calyx tube) greatly dilated, and enclosing within its cellular flesh the five cartilaginous carpels which constitute the "core" and are really the true fruit. From the upper rim of the receptacle are given off the five sepals, the five petals, and the very numerous stamens. Another major relative of the pear (and thus the apple) is the quince.
The form of the pear and of the apple respectively, although usually characteristic enough, is not by itself sufficient to distinguish them, for there are pears which cannot by form alone be distinguished from apples, and apples which cannot by superficial appearance be recognized from pears. A major distinction is the occurrence in the tissue of the fruit, or beneath the rind, of clusters of lignified cells known as "grit" in the case of the pear, while in the apple no such formation of woody cells takes place. The appearance of the tree—the bark, the foliage, the type of inflorescence (i.e. form of the flower cluster)—is, however, usually quite characteristic in the two species.
The cultivation of the pear in cool temperate climates extends to the remotest antiquity. Many traces of it have been found in the Swiss lake-dwellings. The word "pear" or its equivalent occurs in all the Celtic languages, while in Slavonic and other dialects different appellations, but still referring to the same thing, are found—a diversity and multiplicity of nomenclature which led Alphonse de Candolle to infer a very ancient cultivation of the tree from the shores of the Caspian to those of the Atlantic.
Pears grow in the sublime orchard of Alcinous, in Odyssey vii: "Therein grow trees, tall and luxuriant, pears and pomegranates and apple-trees with their bright fruit, and sweet figs, and luxuriant olives. Of these the fruit perishes not nor fails in winter or in summer, but lasts throughout the year."
The pear was cultivated also by the Romans, who did not eat them raw: Pliny's Natural History recommended stewing them with honey and noted three dozen varieties. The Roman cookbook attributed to Apicius, De re coquinaria, has a recipe for a spiced stewed-pear patina, or soufflé (IV.2.35).
A certain race of pears, with white down on the under surface of their leaves, is supposed to have originated from P. nivalis, and their fruit is chiefly used in France in the manufacture of Perry (see Cider). Other small-fruited pears, distinguished by their early ripening and apple-like fruit, may be referred to P. cordata, a species found wild in western France, and in Devonshire and Cornwall. Pears have been cultivated in China for approximately 3000 years.
The genus is thought to have originated in present-day western China in the foothills of the Tian Shan, a mountain range of Central Asia, and to have spread to the north and south along mountain chains, evolving into a diverse group of over 20 widely recognized primary species. The enormous number of varieties of the cultivated European pear (Pyrus communis), are without doubt derived from one or two wild species (P. pyraster and P. caucasica), widely distributed throughout Europe, and sometimes forming part of the natural vegetation of the forests. In England, where an ancient pear tree gave its name to Pirio (Perry Barr, a district of Birmingham) in Domesday, the pear is sometimes considered wild; there is always the doubt that it may not really be so, but the produce of some seed of a cultivated tree deposited by birds or otherwise, which has germinated as a wild-form spine-bearing tree. Court accounts of Henry III of England record pears shipped from Rochelle and presented to the King by the Sheriffs of London. The French names of pears grown in English medieval gardens suggests that their reputation, at the least, was French; a favored variety in the accounts was named for Saint Rule or Regul', bishop of Senlis.
Asian species with medium to large edible fruit include P. pyrifolia, P. ussuriensis, P. ×bretschneideri, P. ×sinkiangensis, and P. pashia. Other small-fruited species are frequently used as rootstocks for the cultivated species. Etymology:
Pears are native to coastal and mildly temperate regions of the Old World, from western Europe and north Africa east right across Asia. They are medium sized trees, reaching 10–17 m tall, often with a tall, narrow crown; a few species are shrubby. The leaves are alternately arranged, simple, 2–12 cm long, glossy green on some species, densely silvery-hairy in some others; leaf shape varies from broad oval to narrow lanceolate. Most pears are deciduous, but one or two species in southeast Asia are evergreen. Most are cold-hardy, withstanding temperatures between −25 °C and −40 °C in winter, except for the evergreen species, which only tolerate temperatures down to about −15 °C.
The flowers are white, rarely tinted yellow or pink, 2–4 cm diameter, and have five petals. Like that of the related apple, the pear fruit is a pome, in most wild species 1–4 cm diameter, but in some cultivated forms up to 18 cm long and 8 cm broad; the shape varies in most species from oblate or globose, to the classic pyriform 'pear-shape' of the European Pear with an elongated basal portion and a bulbous end.
There are about 30 primary species, major subspecies, and naturally occurring interspecific hybrid of pears.
The pear may be readily raised by sowing the pips of ordinary cultivated or of wilding kinds, these forming what are known as free or pear stocks, on which the choicer varieties are grafted for increase. For new varieties the flowers can be cross-bred to preserve or combine desirable traits. The fruit of the pear is produced on spurs, which appear on shoots more than one year old.
Other species are used as rootstocks for European and Asian pears and as ornamental trees. The Siberian Pear, Pyrus ussuriensis (which produces unpalatable fruit) has been crossed with Pyrus communis to breed hardier pear cultivars. The Bradford Pear (Pyrus calleryana 'Bradford') in particular has become widespread in North America and is used only as an ornamental tree. The Willow-leafed Pear (Pyrus salicifolia) is grown for its attractive slender, densely silvery-hairy leaves.
Pears can be useful in treating inflamation of mucous membranes, colitis, chronic gallbladder disorders, arthritis, and gout. Pears can also be beneficial in lowering high blood pressure, controlling blood cholesterol levels, and increasing urine acidity. They are good for the lungs and the stomach. Most of the fiber is insoluble, making pears a good laxative. The gritty fiber content may cut down on the number of cancerous colon polyps. Most of the vitamin C, as well as the dietary fiber, are contained within the skin of the fruit.