ARBOKICULTUBE 321 The flowering or manna ash (Fraxiuus Ornus), a native of the mountains of South Italy, is a handsome tree, de serving a place in ornamental plantations. It has a fine effect standing singly on a lawn. The medicinal manna it yields is obtained by making incisions in the stem. Catalpa syringccfolia is a splendid tree when in flower : it attains the height of 30 or 40 feet, and sometimes ripens its seeds in the climate of London ; but in the northern counties it seldom does much good. It bears a very severe cold in winter, provided there has been heat and sunshine enough in summer to ripen its wood. Of the genus Quercus, 281 species, European, American, and Asiatic, are described in De Candolle s Prodromus, and a great variety are procurable in British nurseries. The best known European species are Q. Suber, the cork oak ; Q. Cerris, the Turkey or mossy cupped oak ; Q. jEgilops, the Vallonea oak ; and Q. lusitanica infectoria, the gall or dyer s oak. The Lucombe and Fulham oaks are believed to be hybrids between Q. Cerris and Suber. Q. Ilex, the evergreen or holm oak, a native of South Europe, Persia, and the North-West Himalaya, but introduced into Britain in 1581, and commonly planted, attains a large size, and frequently ripens its acorns. The oaks of; North America are very numerous and interesting, but they do not ripen their shoots sufficiently to be frost-proof. None of the deciduous Himalayan species have yet been successfully introduced. PROPAGATION AND CULTURE IN THE NURSERY. Nursery Culture. A nursery is a plot of ground devoted to the propagation and rearing of trees; it should as far as possible be exempt from the influence of frost, which pre vails in low situations, and it ought to contain a variety of soils. As a general principle, all seeds will germinate in any soil provided it contains vegetable matter, and is friable, free of stones, and well drained, with a convenient supply of water. If a nursery therefore contains the three leading soils, sand, loam, and peat, it will suffice for all required purposes. With regard to climate, all deficiencies which occur in Britain may be met by glazed frames for raising the more tender kinds. It is the interest of the nursery man to have his nursery in a fine climate, and in deep fer tile soil, that he may raise large vigorous plants in the shortest period ; but it is the interest of the purchaser to have the plants reared in a climate and soil inferior to that into which they are to be transplanted, because, when this is done, instead of the plants receiving a check, as is usually the case, they will be improved by transplanting. The strength of a plant and its suitableness for successful trans planting consists in all its parts being developed, in the thorough ripening of its wood, and in the dormant state of its fibrous roots. If by any mode of culture these requisites can be obtained, together with the long and thick shoots which are produced by growing the plants in deep rich soil, so much the better ; but in the climate of Britain trees reared in nurseries with inferior and unmanured soil are likely to prove most hardy. Those who plant in moun tainous districts will always find it better to have their nurseries on the sides of mountains than in the valleys. Propagation. Trees are chiefly propagated by seeds, but also by cuttings, layers, budding, and grafting. The timber-trees of all countries are raised from seeds, with a few exceptions, such as the poplar and willow, which are raised from cuttings, and some species of elm, lime, and a few others, which are raised from layers or by grafting. Most ornamental trees are raised by some of these artificial methods, because in this country they seldom ripen seeds. Thus, all the American oaks may be grafted on the common British oak. Most of the foreign maples and birches are raised by layers, most c f the ornamental thorns by budding and grafting, and willows and poplars by cuttings. All plants which do not ripen seeds readily are propagated artificially, and that mode is preferred by the nurseryman, which experience has proved will produce the largest and most vigorous plants in the shortest time. Thus, though more suitable plants would be produced by raising the plane and poplar from cuttings, because in that case nature would adjust the tops to the power of the roots, yet as much larger plants are produced by layers, that mode is preferred in commercial nurseries. The lime tree and English elm ripen their seeds in Britain, but large plants are much more rapidly procured in the first case by layers, and in the second by grafting: the mode by which the largest plants are most rapidly produced need not always give way to the slower method; but in most cases, it would be advantageous to the purchaser that the slower mode should be adopted. According to some writers, seedling plants are of greater durability than those raised in any other way; but though this may be true in some cases it is not universally applicable, as we know that a bud pro duces as perfect a plant as a seed; the only difference being that the bud seems more fully imbued wtth the peculiarities of the individual which produced it than the seed. The poplar, willow, vine, &c., have been propagated by cuttings from time immemorial, and appear to possess respectively the same properties now that they did in the days of the Romans. Seeds should be collected when, mature from the best specimens; and should either bo. sown immediately, or preserved in a place where they will, undergo few atmospheric changes till the proper sowing season, which in most cases will be the following spring. Nature, it may be observed, sows all her seeds soon after they are matured; that is, they drop from the tree upon the ground in autumn or the beginning of winter, or, in the case of some trees, such as the conifers, not till spring ; but when seeds are thus left to sow themselves many are destroyed by animals, many fall in unfavourable positions for germination, and only a small proportion produce plants. It is for the arboriculturist to study nature s mode of sowing, and to imitate only her favourable features. The greater number of seeds may be stored till the following spring, that is, till February or March, and then be com mitted to the soil. Poplar and willow seeds, however, ripen early, and when sown immediately on dropping from the tree, often come up in the course of a few weeks ; whereas, if they are kept till spring, the greater number do- not come up at all ; and seeds which lie two years in tha ground before coming up, such as those of the hawthorn, the holly, &c., may be kept till the second spring before they are sown. In order to show the treatment required for different kinds of seeds, and the plants raised from them, it will be convenient to throw them into the following groups : Trees producing (1) cones; (2) nuts, acorns, masts, or keys ; (3) cottony or feathery seeds ; (4) fleshy fruits ; or (5) leguminous seeds. Coniferous Trees. Coniferous trees ripen their seeds from October till January, and if the cones remain on the tree throughout the winter the seeds do not gene rally drop out till .April or May; such as drop into favour able soil come up in five or six weeks. The cones should be collected immediately after they are ripe, and laid in a dry place. The seeds are extracted by exposing the cones to the heat of the sun under glass, or by subjecting them to artificial heat before an open fire, or on a kiln. The seeds are sown in April, in soil dug over and finely raked , and then covered with a thin coating of soil. The beds, after the sowing is completed, should be shaded from the sun by branches of tree. In cold moist climates, such an that of Aberdeen, this shading may be dispensed with :
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