In France the Acacia tree appears to have been more generally diffused throughout the country than in England]; for it does not only ornament their gardens, and shade their public walks, but the sprightly foliage of this beautiful tree shines through their woods and forests in every direction; so much so that it might be taken for an indigenous inhabitant of the soil.

In one of the Memoirs by the Agricultural Society at Paris, the properties of this tree are very highly extolled. Its shade, it is said, encourages the growth of grass. Its roots are so tenacious of the soil, and shoot up such groves of suckers, that when planted on the banks of rivers it contributes exceedingly to fix them as barriers to check the incursions of the stream. Acacia stakes, too, are more durable than any other known wood.

The choicest pieces only of the best oak timber are applied to the purpose of trenail- | making in ship-building; and, as the Sussex oaks are generally reckoned the best, most shipwrights, even in the north, have them from thence, and the demand for them is so great, that trenail-making is there become a very considerable manufacture. If it be proved that the Acacia tree is equal to our best oak for this important purpose in our naval architecture, then do we strongly recommend (and we write practically) to every landed proprietor to plant the Acacia as a forest tree, more especially as it will grow upon almost any description of soil, but more particularly upon sandy or gravelly shallow soils, where the oak does not thrive.

In forty years the Acacia tree will grow sixty feet high, and will girth six feet, three feet from the ground; and, although brittle in a young state, the characteristics of the timber of a grown tree are toughness and elasticity.

As a durable timber, it has been proved that nothing can exceed the Acacia wood, when of proper age. But there is one important use to which these trees may be applied, which has hitherto escaped the notice of the planter, namely, hedges. From its rapidity of growth it forms a fence capable of resistance in onefourth of the time of any other plant hitherto used for that purpose. Had we to fence in a whole estate, we should, in preference to all others, plant Acacias. They bear clipping, and may be raised to twenty or thirty feet high, if required, and are so strong that no animal can force through them. The only instance of an Acacia hedge we know of, on the continent of Europe, is to be seen round part of the boulevard the city of Louvain. Plants for this purpose should be taken from the nursery lines four feet high. At every point where the stems cross one another, a natural union or grafting takes place, and, as the stems increase in size, the spaces between will gradually decrease; so that in the course of a few years the fence becomes a complete wooden wall, not occupying a space more than twelve or fifteen inches, forming a barrier that no animal can force. Fences of this description nay either be made on the level ground, or concealed from the distant view.

It is difficult to account for the name com monly given to this tree by the Americans, namely, Locust tree; for the Locust tre (Hymenau Courbaril) is a native of Soutı America.

In the arboretum of the gardens of the Horticultural Society of London, there is a proof, perhaps the very best proof that this country affords, of the great rapidity of growth, and also the beauty of this truly interesting and highly valuable tree. About twelve years ago. this aboretum was planted for the express purpose of introducing the trees of all countriesthe research of enterprising men. The Acacia was planted with the other individuals of this very splendid collection, and the result has been, that the Acacia has made greater progress than any of the oaks, the ash, the elm, the maple, or, indeed, any of the hardwooded timber trees within the wall of the gardens.

The Acacia trees, in their rapidity of growth, are exceeded only by a few of the poplar and willow tribes.

There is a singular character about the suckers of this tree. They are rarely seen to appear on the lawn, but in the shrubbery frequently. They rise singly, not like the elm, and other trees, in thick masses, choking one another, but they start out of the ground at once, with all the boldness and vigour of a healthy shoot from a powerful stool; and in a sheltered situation will grow, the same year, from twelve to fifteen feet long from the ground; and it is the more remarkable, that these suckers grow in this vigorous way immediately under the shade of the parent, and other large trees. What is also very singular, so strongly are they attached to the root below the ground, at the insertion, that they are very rarely from accident displaced.

Mr. William Lindsey mentions a very striking instance of the astonishing rapidity of the growth of this tree. He observed a strong shoot make its appearance in one of the woods at Chiswick, and he had the curiosity to see what would be the result by applying a stake to this sucker for protection. By the end of the season, it was twenty feet high, and measured three inches in circumference. When the full-grown old Acacia trees are felled, the following year hundreds of suckers will start up from the roots in directions, and grow as freely as if a fresh plantation had been carefully made. So that, on the score of economy, we know of no tree that can be planted equal to the Acacia. As an underwood, it far exceeds any other tree in produce and for stakes, arbour-poles, hop-poles, and for pale-fencing, there is no wood equal to the Acacia. In America, the use of the Acacia has been confined to trenails of ships, in consequence of its scarcity. But were it, either in that or this country, as plentiful as oak, it would be applied for more purposes in naval architecture, such as knees, floor-timbers, and foot-hooks, being far superior to oak for its strength and duration; and from the tree ar riving much sooner at perfection, and spread. ing into so many branches, it affords full as

In modern botany, Acanthus is a genus of herbaceous plants found in the South of Europe, Asia Minor, and India, belonging to the natural order Acanthaceæ.

ACCLIMATION OF PLANTS. This term has been applied to the act of accustoming plants to support a temperature or a climate different from that in which they are found originally growing. This differs from naturalization, which is the act of transporting or transferring a plant into a country different from its native place of growth. Nobody can deny the possibility of these naturalizations; but there are some doubts upon the acclimations of plants, doubts which have been corroborated by M. Schubler (Linnæa, 1829, p. 16); and it renders this important question the more deserving of examination, that the facts which are reported are complex and somewhat contradictory.

Europe, and consequently little known, is cul tivated in the open ground, it often happens that it is placed in a soil or a position contrary to its nature, that it is watered too much or too little, and that it is pruned unseasonably, and the like; it consequently perishes without the temperature of the climate being to blame Some years afterwards its nature becomes better known, and the management which it re quires; it is planted anew in the open ground is properly cultivated, and it succeeds, and we then say it is acclimated, while it is simply naturalized.

The greater number of cultivators think that plants produced from seeds collected in the same country are much stronger than those produced from foreign seeds, and make this an argument to prove the doctrine of acclimation. Sir Joseph Banks (Trans. Hort. Soc. i. 21), in particular, adduces in favour of this opinion the culture of Zizania aquatica, established by him at Spring Grove; but he also

On the one hand, we see wild plants appear fixed within the same climate from the epoch of which we have any knowledge, and culti-relates that the first seeds collected in England vated trees, such as the olive, that have for many centuries kept within the same limit.

On the other hand, we see certain trees, such as the horse-chestnut, which, although originally from the tropics, have reached as far north as Sweden. We see that in gardening, the Aucuba japonica and the Pæonia Moutan, after having been cultivated in the hothouse, have passed into the greenhouse, and now flourish in the open air. But before we infer from these facts the possibility of acclimation, it will be necessary to analyze them more fully.

produced delicate plants, and the second strong plants, so that this example proves as much against as in favour of the theory. Dr. Macculloch, also (Journ. of Science, 1825, p. 20; Feruss. Bull., Sc. Agr., ix. p. 262), in his Essay on the Island of Guernsey, strongly doubts this pretended superiority of plants coming from seeds. We will not stop to notice that this opinion is in opposition to the very generally received idea, that the changing of seeds is useful. We do not think it less probable that those seeds taken from trees supposed to be Taking the instance of a plant which may languishing, in consequence of not being yet have been placed at the first in the hothouse, properly acclimated, produce young plants and afterwards cultivated in the open ground, much stronger than those which are taken what are we to conclude, but that, while igno- from trees more healthy, and growing in their rant of its nature, and while its rarity rendered natal soil. We will not discuss that which it more precious, we were unwilling to run the certain cultivators, such as M. J. Street (Trans. risk of losing it. There is not a gardener, or Hort. Soc., viii. 1; Ferussac, Bull., Agr.), assert, one who has had the management of a botanic that the individual plants coming from cuttings garden, who has not made such calculation a are much stronger than those coming from hundred times, and who, doubtful of success, seeds; but we will ask whether this experihas been led to follow this prudent course with ment has been made with any degree of cera multitude of plants. Those plants which are tainty, that is to say, in a comparative manner; received from tropical countries are usually and when the fact is so, that native seeds have thus treated, on the supposition that they par- had better success, whether this may not have take of the general nature of plants brought arisen from the circumstance that certain sorts from those countries; and we afterwards try, of seeds do not succeed well when they are not by groping in the dark, those which form ex- sown immediately after maturity, as in the case ceptions to the general law. We thus succeed of the coffee plant, or perhaps from their being in naturalizing some of them; but this does not a greater number of seeds to dispose of, and yet prove that they have been acclimated, for more of them sown? In fine, supposing that they have not been exposed on their arrival in experiments are in accordance with the adthe climate they were afterwards seen to sup-mitted opinion, does this prove any thing more port. Even had this been done, the experiment than that a tree which produces good seed is would have been frequently doubtful; for when of a nature to accommodate itself to the soil; plants arrive in Europe they are for the most part weak, and too young to try the experiment with; while every one knows that young plants, such as those of the bead tree and the silk tree, will thrive in a temperate climate in their adult age, if they are very vigorous when planted, but which are easily destroyed by the frost when young.

An exact knowledge of the manner of living of each species tends to explain some of the illusions which we are apt to fall into on this subject. Thus, when a plant newly arrived in |

and is not this rather a proof of naturalization than of acclimation? Let us see if there exist any clearer proofs of the reality of acclimation.

One of the principal results of culture is the formation of varieties which otherwise would have no existence in nature, and which have different degrees of susceptibility according to the temperature. We know that these varieties, in many instances, are much more delicate than the wild species. We may instance varieties of double flowers, which are

hardy than those of single varieties of the same species; varieties of white flowers, which are generally less hardy than red or yellow varieties; and the varieties of the oleander, with double rose-red flowers, and with single white flowers, are often killed by the frost, while the common oleander, with single rosered flowers, may stand the winter.

It is, however, those species produced by culture, and chiefly by hybridizing, which are of a more hardy nature than the wild species. Now we conceive that the choice of these vaieties affords the means of introducing certain rts into climates where the original species ould not have succeeded. This effect is most apparent in such varieties as have undergone some change in the season of vegetation: thus the late variety of the walnut tree, which we call St. John's walnut, will thrive in those localities where the frosts are felt late in the spring, and where the common walnut tree is soon killed by the cold. Thus the very early varieties of the vine will bear fruit in certain climates, where either from there being little heat, or from the rapid approach of autumnal frosts, other varieties would not succeed.

tables are susceptible of being acclimated, this occurs within very narrow limits; and we frequently exaggerate these limits by confounding acclimation with naturalization. 2. That the cases in which acclimation appears to take place in reality, chiefly, if not exclusively, comprise species where there is a formation of new varieties, or where we have managed to change the season of the vegetation of plants, as arising from periodicity. 3. That practical results, almost as important as those of acclimation, more properly so called, are obtained by ably following up certain processes of culture. (Miller's Dictionary.)

[A sensible and eloquent writer in the American Journal of Geology, has, in a paper upon the " Acclimating Principle of Plants," treated the subject in a highly interesting manner, and illustrated it by referring to many instances where plants have actually adapted their growth and habits to a great extent of country, and diversity of latitude. His views, it will be seen, are not in exact accordance with those contained in the preceding article upon a similar topic. They are, however, calculated to be particularly interesting in the meridian of the United States.

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There exists, in many species of plants, the remarkable phenomenon of certain individuals Plants," observes the writer referred to being more early or more late than others, with- "have directly no locomotive powers, but indi out our being able to attribute the circum-rectly, they have in a great degree the faculty stance to the influence of locality; while, at the same time, we cannot perceive any sensible difference in the organization. Now, by carefully collecting the seeds, or the layers, or the tubercles, or grafts, of such early and late varieties, we obtain artificially such agricultural sorts or varieties as present certain useful qualities, and such, in particular, as will thrive in climates where the original species would not succeed. For example, by gathering the tubers of such potatoes as ripen first, and by repeating the same, many times in succession, we may by this means obtain a variety which will ripen in three months. To us, such a variety is of no more advantage than in giving us an early vegetable; but if cultivated in climates farther north, it might introduce the useful culture of the potato in places where this was previously unknown. Attentive observation of such species and varieties may furnish means of advancing the culture of certain vegetables beyond their ordinary limits. For example, if the varieties of the olive brought from the Crimea, which appear less affected with cold than European varieties, should come to be introduced on the shores of the Mediterranean; or if they should propagate extensively the variety called Caillou in Provence, we might be led to conclude that the olive is accustomed to a greater degree of cold, although there might only be the substitution of a hardier sort for a more delicate

one.

In fine, although we are not authorized to observe that the vegetable tissue cannot, by the effects of habit, accustom itself to a different temperature than that of its native climate; and although we are disposed to recognise, in many cases, this influence of habit, yet the preceding facts seem to lead to the following interences: 1. That if certain species of vege

of changing their places, and, consequently, their climate. The embryo germ wrapped in a kernel, or seed, is virtually a plant, ready to germinate when thrown upon its parent earth, and affected with heat and moisture. It is in a most portable shape, and can be transported with ease to an unlimited distance. Nature in many instances superadds to seeds, wings, down, feathers, and chaff, by which they become buoyant, and are carried by the winds of heaven, by the storms that sweep the forest, and by the streams, and currents of rivers, and the ocean, to an immense distance, and through many degrees of latitude! They become finally deposited in some genial soil, and at one remove, or through a succession, they occupy extensive regions. Nature manifests her great care of the embryo, by coating some of her seeds with shells, which protect them from the attacks of insects, and the action of the elements; others have bitter, narcotic, or poisonous qualities, which forbid animals eating them; and many are filled with oily, or resinous matter, which resists, for ages, and even centuries, the action of the elements, unless acted upon by the proper degree of heat and moisture. By such qualities they endure, and await a suitable time and conveyance to their destined place, in order to extend and vary their families.

Birds also convey the seeds of plants in their crops over a wide extent, before they become triturated and digested; and when these winged carriers die, or decay, from accident or age, the seeds are deposited, and take root in some distant land. Animals also convey them in their stomachs to a considerable distance, and pass them uninjured by the powers of digestion.

Man, more provident than all, to whom plants are necessary, whose support, whose