Plum (Prunus communis or P. domestica), a species of fruit-tree of the natural order Rosaceæ.
The plum is so familiar as a fruit in all temperate countries as to need no description here. The Wild Plum, or Blackthorn, or Sloe (q.v.), is common in English hedgerows, thickets, and open woods, and occurs more sparingly in similar places in Scotland. It is abundant in Europe generally, and in Russia and central Asia. From the sloe all cultivated varieties of the plum are supposed to be derived, but some conjecture that P. insititia (Bullace, q.v.) and P. spinosa are the parents of some of the types of these varieties. The most reasonable probability is that the several forms of wild plum found in England and in other countries where they abound are merely varieties of one species—P. domestica. Other varieties of plum, besides the Sloe, Bullace, and Damson found wild in England, are the Mussel and the Wine Sour, which are used in cooking and in confectionery, and are regarded as primary varieties of the wild plum. The cultivated varieties of the plum are very numerous; there are larger and smaller kinds, but their value in the dessert is reckoned by their sweetness and flavour rather than by their size. Thus, the Green Gage, a kind with only moderate-sized fruit, is the most esteemed of all. It is the Reine Claude of the French, and the Regina Claudio of the Italians. Magnum Bonum, a very large white variety, though one of the handsomest, is accounted only of second-rate quality. The uses of the plum for dessert in the making of pies, tarts, preserves, and sweetmeats are familiarly known. Prunes are the dried fruit of certain kinds of plum. The finest of all the French prunes are made at Brignole in Provence of the varieties of plum called Perdrigon blanc and Perdrigon violette, which are hence named Pruneaux de Brignole or Brignoles. The manner of converting these plums into prunes is by drying in a slow oven. The fruit is allowed to remain on the tree till it is so ripe that a little shaking would cause it to fall. They are then carefully picked and spread out in the sun on sieves made of lath or wickerwork, till they become soft. Afterwards they are put in a spent oven, and shut up close in it for twenty-four hours, and then taken out. The oven is again heated, somewhat warmer than before, and the plums returned to it till the following day, when they are taken out and turned by slightly shaking the sieve. Again the oven is re-heated, rather warmer than before, and the fruit returned to it for twenty-four hours, and so on till the operation of drying is finished, a point which only experience can nicely determine when reached. Other kinds of prunes of inferior quality are made from the fruit of the Petit Damas, and from the Quetsche, the latter being made in Germany. From this also is distilled a kind of brandy. In Bosnia and Herzegovina nearly 50,000 tons of prunes are produced in a good season. Prunes are nutritious and laxative, and stewed in water are excellent diet in cases of costiveness, and during convalescence from fevers and inflammatory complaints. They impart their laxative quality to the water in which they have been stewed, and thus a pleasant and beneficial decoction may be prepared for those who through impairment of the digestive organs cannot eat the fruit. The plum is grown in orchards as standard and bush trees, or they are in the case of the choicer varieties trained to walls. It is not fastidious as to soil, but the finest fruit is produced on strong but well-drained loam. The superior kinds are propagated chiefly by budding and by grafting, the inferior by layers or by cuttings of the roots, the latter being a common method in rearing Damsons in some parts; but the quickest and best method of increasing all is by budding. The wood of the plum-tree is hard and fine-grained, and is used in cabinet-work, in turnery, and for making musical instruments. The Cashmere Plum (P.
Bokharensis), cultivated in Cashmere and Bokhara, is regarded as a distinct species. The Cherry Plum, or Myrobalan Plum (P. cerasifera or Myrobalanus), is a bush very similar to the sloe, with pendulous globular red fruit. It is a native of North America, but is often cultivated for its fruit on the continent of Europe. In Britain it seldom produces fruit. P. maritima is a shrub, indigenous to sandy soils on the seacoast of North America from Massachusetts to Alabama. It has a dark-purple agreeable fruit, about the size of a pigeon's egg. Other native American species are P. chickasa, the Chickasaw Plum, a shrub or small tree of the southern states; P. americana, a bushy tree ranging from Canada to Georgia; and P. glandulosa, of Texas, which is less than a foot high, and has crooked thorny branches.
The Cocoa Plum or Icaco of the West Indies is the fruit of Chrysobalanus icaco, a tree of the natural order Rosaceæ, sub-order Chrysobalaneæ. The fruit resembles a plum, has a sweet although slightly austere taste, and is eaten both raw and preserved. The fruit of Parinari excelsum, another of the Chrysobalaneæ, is called Gray Plum at Sierra Leone.—The term plum is used loosely for the Date Plum (q.v.); and plum or plumb was a word once current for £100,000.