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1 R. P. t crispa Dec. Prod., ii. p. 261.- Prickles wanting. Leaflets all,
or for the most part, undulately curled. 1 R. P.5 umbraculifera Dee. Prod., ii. p. 261., Cat. Hort. Monsp., 157. ;
R. inérmis Dum. Cours., vi. p. 140.- Prickles wanting. Branches much crowded, and smooth. Head orbicular. Leaflets ovate. This variety is said to have been raised from the seed of R. Pseud- Acàcia; and, according to Dumont de Courset, to have yellow flowers. It has been common in British gardens since 1820, but has not yet
flowered in this country. 1 R. P. 6 tortuosa Dec. Prod., ii. p. 261,; and the plate in Vol. II.
Branches much crowded, and twisted. Racemes similar to those of
R. Pseud-Acácia, but smaller and fewer-fowered. ¥ R. P. 7 sophoræfòlia Lodd. Cat., 1830, has the leaves large, and some
what like those of Sophòra japonica. * R. P. 8 amorphefòlia Lk. has leaves somewhat like those of Amorpha
fruticosa. * R. P.9 stricta Lk. has the general tendency of the shoots upright;
but still the plant is not so fastigiate as the Lombardy poplar. * R. P. 10 procera Lodd. Cat., 1830.- A tall vigorous-growing variety. ¥ R. P. 11 péndula Ort. Dec., p. 26.— The shoots are somewhat droop
ing, but not very decidedly so. * R. P. 12 monstrosa Lodd. Cat., 1830.—The leaves are large, and twisted. * R. P. 13 macrophylla Lodd. Cat., 1830, has the leaves long, and the
leaflets broad. Y R. P. 14 microphýlla Lodd. Cat., 1830; R. angustifolia Hort.; has the
leaves small, and the leaflets narrow. * R. P. 15 spectábilis Dum. has large leaves and is without prickles : it
produces straight vigorous shoots, which are angular when young. It was raised from seed by M. Descemet, at St. Denis, and was formerly known in the French nurseries by the name of agaçante
(enticing). 1 R. P. 16 latisíliqua, the broad-podded locust, is mentioned in Prince's
Catalogue for 1829. In America, there are three popular varieties, distinguished by the colour of the heart-wood; viz. the red locust, when the heart-wood is red, and which is esteemed by far the most durable and beautiful timber; the green locust, which is the most common, which has a greenish yellow heart, and is held next in esteem to the red; and the white locust, which has a white heart, and is considered the least valuable of all; and, in the western states, there is said to be another variety, called the black locust. All these may more properly he considered as variations, apparently depending solely on the soil and situation, in the same manner as the blue colour of the flowers of the hydrangea depends on the soil in which it is planted.
Most of these varieties are tolerably distinct in the foliage when the plants are young; but those best worth cultivating, except where there is a complete collection, are R. P. umbraculífera, the parasol acacia; R. P. péndula, the weeping variety ; R. P. stricta, the upright-growing sort; and R. P. spectábilis, the vigorous-growing thornless variety. With regard to the yellow-flowered variety, it may be worth continuing by grafting or suckers; but, to make quite sure of having white flowers, the trees producing them ought to be propagated by grafting also; as plants raised from seed, though, for the most part, they have white flowers, yet occasionally produce yellowish ones.
Description. The Robinia Pseùd- Acàcia, though it attains the height of 70 ft. or 80 ft., with a trunk of 2 ft. or 3 ft. in diameter, in favourable situations in its native country, yet is seldom, if ever, found there with a straight clean trunk, which will admit of being sawn up into boards of even moderate dimensions. It is a much branched tree, with the branches, as well as the trunk, somewhat twisted: the branches have a general tendency upwards when the tree is young, but as it grows old they spread out horizontally. They are armed with strong hooked prickles, and not with spines or ligneous thorns ; the former being only attached to the bark, like the prickles of the common rose or the bramble; and the latter proceeding from the wood, like the spines of the hawthorn, cockspur, and other thorns. The leaves of the robinia are composite, the leaflets being sessile, and 8, 10, or even 12, with an odd one. Their texture is so fine, and their surface so smooth, that the dust which falls on them will hardly lie; which last circumstance renders the tree particularly eligible for planting 305 along road sides, in the neighbourhood of towns, or in great thoroughfares. The flowers are disposed in pendulous bunches, white or yellowish, and are most agrecably fragrant : they are succeeded by narrow flat legumes, about 3 in. long, each containing 5 or 6 small seeds, which are commonly brown, but sometimes black. These seeds, when taken out of the pod, and exposed to the air, will hardly retain their vegetative properties two years, but, when kept in the pod, they will remain good a year longer ; and, when the pods are buried 5 ft. or 6 ft. under the surface, in dry soil, they have been known to keep, 7 years, without losing their vitality, and would probably retain it for a much longer period. The dimensions of the tree, in its native country, vary much with the soil and climate in which it grows. In Kentucky, the tree sometimes attains the height of 70 ft. or 80 ft., with a trunk 4 ft. in diameter; but it does not arrive at half that size at Harrisburgh, in Pennsylvania. On the trunk and large limbs of the old robinias, the bark is very thick, and deeply furrowed; but on the young trees it is comparatively smooth for the first 10 or 15 years. The young tree, till the trunk attains the diameter of 2 in. or 3 in., is armed with formidable prickles ; but these disappear altogether as it grows old, and they are wanting, in some of the varieties, even when they are young. The wood, which is commonly of a greenish yellow colour, marked with brown veins, is hard, compact, and susceptible of a bright polish : it has a good deal of strength, and is very durable; but it has not much elasticity, and is somewhat liable to crack. The tree has one property almost peculiar to it, that of forming heart-wood at a very early age, viz. in its third year; whereas the sap-wood of the oak, the chestnut, the beech, the elm, and most other trees, does not begin to change into heart, or perfect, wood, till after 10 or 15 years' growth. (Michr.) In Britain, in the neighbourhood of London, the Robinia Pseud-Acàcia sometimes attains as great a height as it does in any part of America; but, north of London, it is as small as it is in the north-east of Pennsylvania, or smaller. It grows with great rapidity when young; plants, in 10 years from the seed, attaining the height of from 20 ft. to 30 ft., or even 40 ft.; and established young plants producing shoots 8 ft. or 10 ft. long in one season. When the tree has once attained the height of about 40 ft. or 50 ft., it grows very slowly afterwards; but, whatever height it attains, there are very few specimens to be met with in England, that have more than 30 or 40 cubic feet of timber in the trunk. At 50 or 60 years of age, the trunk is not greatly increased in girt; but at that age the branches often contain as great a bulk of timber as the trunk, though, from not being straight, that timber is comparatively of little value, except for fuel. The greatest bulk of timber contained in any robinia that we have heard of is in one at Taverham, in Norfolk, which contains 89 cubic ft. (Withers's Treat., p. 234.) It stands among some silver firs, which are presumed to be about the same age, and which contain nearly 3 loads (about 150 ft.) of timber each; thus affording a tolerable criterion of the comparative rate of growth of the two trees. The trees of this species, and of several of its varieties, in the garden of the Horticultural Society, and in the arboretum of Messrs. Loddiges, have attained the
height of 30 ft. and upwards, in 10 years from the time they were planted. Cobbett and Withers record instances of much more rapid growth. The former, in his Woodlands (382.), mentions a plantation at Coleshill, in which the trees averaged 19 ft. after being 4 years planted; and others at Botley, which, in 11 years had attained the height of 40 ft., with trunks “3 ft. 2 in. round at the bottom.” (Ibid., § 358.); and in Withers's Treatise, p. 254., mention is made of 900 plants, placed 4ft. apart in 1824, which, in 1828, had reached to from 13 ft. to 16 ft. in height, and were to be cut down, and used as hop-poles.
A plantation of locusts, Scotch pines, sycamores, limes, Spanish chestnuts, beeches, ashes, and oaks was made in 1812, at Earl's Court, near Kensington, and the trees measured, at Cobbett's request, in 1827; when it was found that the locust had grown faster than any one kind of the other trees in the proportion of 27 to 22, and faster than the average of them in the proportion of 27 to 18. (See Woodlands, J. 375., and Gard. Mag., vol. iii.p. 363.) This comparatively rapid growth of the locust, which is in a great measure confirmed by other measurements in Mr. Withers's Treatise, is owing to the spreading roots of the tree having the power of more rapidly extracting nourishment from the soil than the descending roots of the other trees among which it was planted; but these other trees, with descending roots, though they grow slower than the locust at first, would, in the course of 30 or 40 years, overtop it, and ultimately destroy it altogether, as has been proved in the Bois de Boulogne near Paris.
Geography. In North America, the locust tree, as it is there called, begins to grow naturally in Pennsylvania, between Lancaster and Harris burgh, in the lat. of 400 20%: west of the Alleghanies, it is found 2° or 3° farther north; because, on the west side of these mountains, the climate is milder, and the soil more fertile than on the east of them. It is most abundant in the south-west, abounding in all the valleys between the chains of the Alleghany mountains, particularly in Limestone Valley. It is common in all the western states, between the Ohio, the Illinois, the lakes, and the Mississippi. It is plentiful in Upper Canada, and also in Lower Canada; but it is not found in the states east of the river Delaware, nor does it grow spontaneously in the maritime parts of the middle and southern states, to the distance of from 50 to 100 miles from the sea. It is planted, however, in that region for purposes of both utility - and ornament. It is observed by Michaux, that the locust forms a much smaller proportion of the American forests than the oaks and walnuts, and that it is nowhere found occupying tracts, even of a few acres exclusively. Hence the tree, where it is met with, is frequently spared by settlers, as being ornamental, and comparatively rare; in the same manner as the black walnut is frequently spared for the same reasons, and for its fruit. Hence, also, old specimens of these two trees, which have belonged to the aboriginal forests, are frequently seen growing in the midst of cultivated fields.
History. There is, perhaps, no American tree respecting which so much has been said and done, in Europe, as the locust. It was one of the first trees that we received from that country, and it has been more extensively propagated than any other, both in France and England. It has been alternately extolled and neglected in both countries; and even at the present time, though the beauty of its foliage and flowers is generally acknowledged, and though it has, at different periods, been enthusiastically praised by different writers, for the valuable properties of its wood, it cannot be considered as holding a high rank as a timber tree, or as being generally planted with a view to profit.
The seeds of this tree, it is stated in Martyn's Miller and most other British works, and even in the Nouveau Du Hamel and Baudrillart's Dictionnaire, were first sent to Europe to Jean Robin, gardener to Henry IV. of France, in 1601 ; but, according to Deleuze, as quoted, p. 136., and also to Adanson, in the article Acàcia, in the French Encyclopædia, the locust was sent from
America to Vespasian Robin (son to Jean Robin), who was arborist to Louis XIII., and was planted by him in the Jardin des Plantes in 1635.
In England, it appears to have been first cultivated by the elder Tradescant; but whether he obtained it from France, or direct from Virginia, is uncertain. It is highly probable, that he may have received it from America even before Robin, as Parkinson, in his Theatre of Plants, published in 1610, mentions the tree as having been grown by Tradescant “ to an exceeding height.”. The first tree planted in Paris still exists (as noticed p. 136.); and the first tree planted in Germany, in 1696, still remains, though in a very decayed state, in a court-yard in Vienna (as noticed p. 147.). Tradescant's tree was in existence when Sir William Watson visited his garden in 1749. (See p. 40.) The earliest notice of the robinia in England is that in Parkin. son's Theatre of Plants, before referred to: it is not mentioned by Gerard, either in the first edition of his Herbal, published in 1597, or in that edited by Johnson, in 1629. Evelyn, in the first edition of his Sylva, published in 1664, says, “The French have lately brought in the Virginian acacia, which exceedingly adorns their walks. The tree is hardy against all the invasions of our sharpest seasons; but our high winds, which, by reason of its brittle nature, it does not so well resist; and the roots (which insinuate and run like liquorice under ground) are apt to emaciate the soil, and, therefore, haply not so commendable in our gardens as they would be agreeable for variety of walks and shade. They thrive well in His Majesty's new plantation in St. James's Park.” (Sylva, ed. 1664, p. 64.). In the edition of the Sylva published in 1706, Evelyn speaks of two acacias, the gleditschia and the false acacia ;“ both which,” he says, “ deserve a place among avenue trees, and love to be planted among moist ground.” Mortimer, in 1712, says, “ A great number of acacias were formerly planted in St. Janes's Park; but, in consequence of some of their branches being broken by the wind, they were all cut down.” Bradley, in 1718, speaks of the Virginian acacia as the only species of that tree that will stand the open air in England, and refers to some of them growing in the court before Russell House, Bloomsbury (now the British Museum), and in the Old Palace Yard, Westminster. None of these trees now exist. Ray, in his History, published in 1719, mentions the robinia as among the trees growing in the Bishop of London's garden at Fulham. According to Lysons there were two trees there in 1809; and the remains of one of them still exist (1836). (See p. 43.) Miller, in 1731, speaks of the robinia as very common in gardens near London, where there were, in his time, several large old trees. He says that they are very hardy, but will not endure being exposed to high strong winds, which break their branches, and render them unsightly. “Many people,” he adds, “ have neglected to cultivate them on that account; but they will do well if planted in wildernesses among other trees, where they will be sheltered, and make a beautiful variety.” Miller mentions one 40 ft. high as a large tree; and he also states that, in his time, the robinia had ripened seeds in England, from which young plants had been raised. In 1752, he says that the robinia was generally propagated in English nurseries by suckers from the roots of old trees, but that he prefers raising them from seeds. Young plants, he says, frequently make shoots of from 6 ft. to 8 ft. in length in one season. “ These trees,” he adds, “ were formerly in great request in England, and were frequently planted in avenues, and for shady walks; but their branches being generally broken or split down by the wind in summer, when they are clothed with leaves, the trees are rendered improper for this purpose; and their leaves coming out late in the spring, and falling off early in the autumn, occasioned their being neglected for many years ; but of late they have been much in request again, so that the nurseries have been cleared of these trees; though, in a few years, they will be as little enquired after as heretofore, when those which have been lately planted begin to have their ragged appearance.” (Dict., 6th edit. in 1752.) In the seventh edition of his Dictionary, published in 1759, Miller says that young trees, two or three
years' seedlings, are 8 ft. or 10 ft. high. In Dr. Hunter's edition of Evelyn's Sylva, published in 1786, we have a history of the employment of the robinia in ship-building, communicated to the doctor by Joseph Harrison, Esq., of Bawtry, in a letter dated July 25. 1782. This gentleman had resided some time in Virginia ; and he states that, about the year 1733, the first experiment was made respecting the application of the locust tree to any purpose in ship-building, by an ingenious shipwright, sent over to America by some Liverpool merchants to build two large ships there. This shipwright thought“ that the oaks, elms, ashes, and many other timber trees common to both countries, were much inferior to the same sorts in England; but frequently spoke of the locust tree as of extraordinary qualities, both in strength and duration." He had observed some very old timber in houses in New England, that had been built of the wood of this tree, when the country was first settled, perfectly firm and sound ; and, after having completed his engagement for his employers, he began to build a small vessel for himself; when, being at a loss for a sufficient quantity of iron, and having observed the extraordinary strength and firmness of the locust tree, he took it into his head that trenails, or tree-nails, that is, wooden pins, of that timber, might be substituted for iron bolts in many places where they would be least liable to wrench or twist (as in fastening the foor timbers to the keel, and the knees to the ends of the beams, which two articles take up a large proportion of the iron used in a ship), purposing, when he arrived in England, to bore out the locust trenails, and drive in iron bolts in their stead. The ship, being finished and loaded, sailed for Liverpool, and returned back to Virginia the next year; and the builder himself being the captain of her, he paid particular attention to see the effect of the locust trenails. After the strictest examination, he found that they effectually answered the purpose intended. It was, however, thought prudent to take several of them out, and to put in iron bolts in their room; and this operation afforded another proof of their extraordinary strength and firmness, as they required to be driven out with what is technically called a set bolt (an iron punch), just as if they had been made of iron; whereas oak trenails are usually bored out with an auger. This captain afterwards died in the West Indies; and the use of the locust for trenails was neglected for some years, till it was revived at the instance of Mr. Harrison, by a ship-builder of eminence at New York, where it has since been in general use. Till the value of the locust tree for trenails, or trunnels, as they are called by Cobbett, was proved in America, they were formed in Britain of the best oak timber ; and, as the oak wood grown in Sussex is generally reckoned the best in the island, oak trenails were sent from that county to every part of Britain ; but at present oak is only partially used for this purpose, locust trenails being imported from America to a very great extent.
Public attention being thus, about the latter end of the last century, powerfully directed to the locust, both in Europe and in America, various pamphlets and papers in the Transactions of societies began to be published on the subject. A Treatise on the Common Acacia was published at Bordeaux in 1762, and a Memoir on it in Paris in 1786. In the latter, it is recommended for planting on the banks of rivers, in order to strengthen the banks by its running roots, and the numerous suckers which they throw up. The writer also recommends it for pea-sticks, hop-poles, vineprops, hoops, wedges, cogs to wheels, &c.; and even as a substitute for saintfoin, as a forage crop, to be mown thrice a year, and either used green, or dried as hay and stacked mixed with straw for winter use. He mentions its various medical properties, and adds that a very agreeable syrup is made from the flowers. There is also a paper on the subject in the Memoirs of the American Academy of Arts, 8c. for 1785. The writer says that the wood, when green, is of a soft texture, but it becomes hard when dry. He considers it as durable as the best white oak; and states that it is esteemed preferable to the timber of that tree, for the axletrees of carriages, trenails for ships, and many other mechanical purposes. It makes excellent fuel, being, like the ash, fit to