and their wood is ripened; they should then be pruned and potted, and kept in a shady situation till taken into the house. Moss roses, introduced into a pit or hot-house on the 1st of October, will blossom by Christmas-day; those on the 1st of November, from the middle of January to the middle of February; those on the 1st of December, from the middle of February to the middle of March; those on the 1st of January, from the middle of March to the middle of April; those on the 1st of February, from the middle of April to the middle of May; and those on the 1st of March, from the middle of May to the middle of June; when some of the earlier varieties of moss rose will be in bloom in the open air. (See the details on forcing the rose, given in the Gard. Mag., vol. i. p. 122.) During the forcing season, the plants ought to be supplied liberally with water of the same temperature as the air in which they are kept, and with as much light and air as can be admitted without chilling them; they may also be watered occasionally with liquid manure. Where a regular system of forcing roses is carried on, there should not be less than four houses or pits; viz. one for commencing the process, in which the temperature should not exceed 50°, and where the plants may remain a fortnight; another, to which they ought to be removed, where the temperature may be 60° or 65°; a third, in which they ought to remain six weeks, or till they begin to flower, when they ought to be removed to the fourth house or pit, where they should be kept at a temperature of 60° (which is about that of living-rooms), to prepare them for being removed thither. (See Encyc. of Gard., edit. 1835, § 6045.) Those, however, who are contented with Ròsa i. odorata, or any other sweetsmelling variety of China rose, may have roses all the winter, without a tithe of this trouble and expense, by keeping them in a house or pit, at the temperature of 50°. Insects. The insects that attack rose trees are of several kinds, all very destructive, and all very difficult to destroy; principally, because the means for their destruction are seldom resorted to till their ravages have commenced. The most numerous of these are the aphides, commonly called green flies, or plant lice, which are well known to all rose-growers. These insects lay their small black eggs in autumn, generally near the axils of the buds, so that the young brood may be conveniently placed for feeding on the tender shoots when they appear. In mild seasons, these eggs are hatched about the latter end of February, and the insects produced are few and inconspicuous, many being generally destroyed by the cold. Those that remain, after twice casting their skins, arrive at their full growth about April, when they begin to breed. According to Richardson, the first brood consists entirely of females; and each of these produces a numerous progeny without the assistance of the other sex. These, though themselves produced from eggs, are viviparous. A third generation appears in May; and the months of June and July each supply two more. In the autumn, the eighth, ninth, and tenth generations are produced; two of them in August, and the last, which consists of both males and females, about the middle of September. From the females of this latter race the eggs are produced which are intended to perpetuate the species for the following year. The parent insects deposit their eggs as near as possible to the branch buds, that the future young may be the more easily supplied with nourishment (as before mentioned); and some continue to lay till the beginning of November. The eggs, at first, are green, but soon become perfectly black: they adhere to the branches by a viscous matter that surrounds them, and remain uninjured by the frost of winter." (Phil. Trans., vol. xli. p. 182.) It will be seen by the above, that the best time for destroying the aphis is while it remains in the egg state, as, if suffered to breed, it multiplies to a frightful extent. For this purpose, wash the stems and branches of the rose bushes, during winter, with a composition of strong tobacco water and soft soap; or, if this be thought too expensive, with water heated to a temperature of 200°; in both cases, cleaning the branches, after the composition or hot water has been applied, with a small painter's brush. Should this precau tionary measure have been neglected, care should be taken to watch for the appearance of the first brood, and, as soon as the insects are perceived, to destroy them with lime or tobacco water, or by fumigation; taking care never to use the nearly boiling water after the buds are expanded, though it will not do the slightest injury before that period. Each succeeding brood being much more numerous than those which preceded it, is more difficult to destroy; till the summer broods, if suffered to appear, completely clothe the young shoots, so as to make them seem nearly three times their natural thickness. In this state, the best remedy is to put lb. of the best strong tobacco into a gallon of hot water, and, as soon as the infusion has become cold, to dip the young shoots into it, letting them remain a few seconds in the water, and, if they are in a very bad state, going over them a second time. After this the shoots should be carefully washed with clean water, and the insect will generally be found to be destroyed. (See Gard. Mag., vol. x. p. 215.) Choice plants may be freed from the aphides by going over the whole plant with a soft brush; laying the infected shoots in the palm of one hand, and brushing off the insects with the other. Pruning is of little use, as the aphides generally attack all the young shoots of a plant at the same time. (See Encyc. of Gard., edit. 1835, p. 1076.) The plants may also be syringed with water in the evening, and then dusted with powdered tobacco leaves, or refuse snuff; or they may be syringed with lime water. The prodigious fecundity of the A'phis ròsæ almost surpasses belief. "Reaumur has calculated that, in five generations, one aphis may be the progenitor of 5,904,900,000 descendants; and in ordinary seasons, there are ten generations produced on rose bushes in the space of nine months." (See Encyc of 547 Gard., p. 1076.) The larva, or grub (fig. 547. b), of the lady-bird (a) should always be spared by gardeners, as it lives on the aphides. This grub is short and thick, of a blackish purple, spotted with yellow or black, and is very active. A few of these insects would soon clear a tolerably large rosarium of the aphides. The larvæ of several flies (Sýrphus Fr.) (c) are furnished with a singular mouth, armed like a trident, with three points, for transfixing their prey, of which they devour amazing numbers. Small singing birds also destroy great numbers. The caterpillars of several small moths, though not so destructive as the aphides, also materially injure the buds and young shoots of rose trees. One of these is of a green colour, with a few black hairs scattered on its body: it sews up the tender leaves by means of silken threads, and takes its station within, concealed from all observation. The leaves of the rose tree are often marked, in autumn, on their upper surfaces, in various directions, with broad brown lines, leaving a narrow black one running down the middle. This curious appearance is produced by the small caterpillar of a minute moth (Microsètia ruficapitélla Steph.), which feeds inside the leaf. The caterpillar, when full grown, is nearly two lines long, and of a yellow orange colour, with a brown mark down the back. It lives upon the thickness of the pulp under the epidermis; and the brown mark is caused by the epidermis drying, in consequence of the insect having eaten the substance of the leaf beneath. The black mark is produced by its egesta, or excrement. The caterpillar is full grown about the 24th of October, when it eats its way out of the leaf for the first time, and crawls down the branches and stem, until it has found a convenient place to fix its cocoon. The perfect insect is called the red-headed pygmy by Haworth; and it is so small, that the expansion of its wings measures only two lines and three quarters. (Ibid.) Others, and perhaps the most destructive, of the insect enemies of rose trees are the caterpillars, grubs, maggots, or larvæ, of one of the saw fly tribe (Tenthredínida), which, when full grown, just before they change into the pupa state, are about half an inch long, and of the thickness of a crow-quill, with a brown, and sometimes rather glaucous, body, and a black head. These caterpillars are, at first, very small, and look like little brown grubs: they generally begin to appear in the latter end of April, or the beginning of May, when the rose-buds on the young shoots are only partially developed. At this season, the bushes should be looked carefully over, and the insects picked off with the hand. If this should be neglected, two or three buds in every cluster will be destroyed, or become what is commonly called wormeaten, producing only damaged or abortive flowers. The leaf-cutter bees also frequently attack rose-leaves, out of which they cut circular 548 pieces to serve for lining their cells. Megachile Willughbiella, and M. centunculàris (fig. 548.)are the kinds that most frequently attack rose trees. GENUS XII. LO`WEA Lindl. THE LOWEA. Lin. Syst. Icosándria Polygynia. Identification. Lindl. Bot. Reg., t. 1261. Synonyme. Rosa sp. Pall. and Lindl. in Ros. Monog Derivation. In compliment to the Rev. Mr. Lowe, Travelling Bachelor of the University of Cambridge; a gentleman now residing in Madeira, from whose botanical investigations of that island we expect important results. (Lindley in Bot. Reg., t. 1261.) Generic Character, &c. The genus Lòwea has been separated from that of Rosa by Dr. Lindley, for the following reasons; which, independently of their application to this genus, we consider to be extremely interesting and important, in a physiological and systematic point of view. It has always appeared to us, since ever we began to think on the subject, that neither genera nor species ought to be founded upon mere technical differences in any one part of the plant, as the orders and classes are in the Linnæan system; but on all the parts of the plant, and on all the circumstances connected with it, as the orders and tribes are according to the natural system. "It is well known," Dr. Lindley observes," that, since the days of Linnæus, the characters of the genera of flowering plants have been exclusively taken from the organs of fructification; while those of vegetation have been rigorously excluded. This has arisen from the former having been supposed, in all cases, to be more constant in their modifications, and less subject to variation than the latter. No other reason can be assigned for the value thus exclusively ascribed to the organs of fructification. It is, however, time that botanists should disembarrass themselves of this ancient prejudice; and that they should admit publicly that by which they are constantly influenced in private; viz. that important modifications of the organs of vegetation are sufficient to divide into genera species which do not essentially differ in the organs of fructification. Of this the Indian cypripediums are one instance; the genus Negúndo is another; and the subject of this article is a third. The structure of the flower of Lòwea is, in every part, that of a rose; but its foliage is not even that of a rosaceous plant; there being no trace of stipulæ. The simple leaves are not analogous to the terminal pinna of a rose leaf; for there is no trace of the articulation upon the petiole, which is required to indicate a reduction of a compound leaf, as we find in Bérberis; neither can they be considered as confluent stipulæ, for the venation is not what would be found under such circumstances, but precisely that of an ordinary leaf.” (Bot. Reg., t. 1261.) 1, L. BERBERIFO`LIA Lindl. The Berberry-leaved Lowea. Identification. Lindley in Bot. Reg., t. 1261. Synonymes. Rosa simplicifòlia Sal. Hort. Allert., 359., Parad. Lond., t. 101., Olivier's Voyage, 5. 49. atl. t. 43.; R. berberifòlia Pall. in Nov. Act. Petr., 10. 379. t. 10. f. 5., Willd. Sp., 2. p. 1063., Ait. Hort. Kew., ed. 2., 3. p. 258., Smith in Rees's Cyclopædia, Redouté Ros., 1. 27. t. 2., Lindl. Rosarum Monog., p. 1., French edition, p. 23., Dec. Prod., 2. p. 602., Spreng. Syst., 2. p. 546., Wallroth Monog., p. 25. Engravings. Bot. Reg., t. 1261.; Parad. Lond., t. 101.; Olivier's Voyage, 5. 49. atl. t. 43.; Nov. Act. Petropol., 10. t. 10. f. 5.; Redouté Ros., 1. t. 2. ; and our fig. 549. Spec. Char., &c. Leaves undivided, without stipules, obovate-cuneate, serrated at the tip. Prickles decurrent, and of the colour of ivory. Sepals entire, subspathulate. Petals yellow, marked with purple at the base. (Dec. Prod., ii. p. 602.) An undershrub, a native of Persia, near Amadan, where it abounds in saltish soil; and also in fields at the bottom of Mount Elwend, and in the Desert of Soongaria. It was introduced in 1790, grows to the height of 2 ft., and flowers in June and July. Varieties, Seringe, in Dec. Prod., has characterised three forms of this species under the name of L. b. 1 glabra Ser.-Prickles upon the stem stipular and scattered. Leaves spathulate. L. b. 3 Redouteana Ser. R. berberifolia Red et Thor. Ros., 1. p. 27., with a correct figure, Description, &c. The plant of this species in the garden of the London Horticultural Society is an undershrub, with recumbent, slender, and rather intricate branches, and whitish leaves. It rarely flowers; and, in regard to its propagation and culture, Dr. Lindley, in the Bot. Reg. for August, 1829, remarks that no more appears to be now known of it, than was at the period of its first introduction in 1790. "It resists cultivation in a remarkable manner, submitting permanently neither to budding nor grafting, nor layering, nor striking from cuttings, nor, in short, to any of those operations, one or other of which succeeds with other plants. Drought does not suit it; it does not thrive in wet; heat has no beneficial effect, cold no prejudicial influence; care does not improve it, neglect does not injure it. Of all the numerous seedlings raised by the Horticultural Society from seeds sent home by Sir Henry Wilcock, and distributed, scarcely a plant remains alive. Two are still growing in a peat border in the Chiswick Garden, but they are languishing and unhealthy; and we confess that observation of them, in a living state, for nearly four years, has not suggested a single method of improving the cultivation of the species." (Bot. Reg., 1261.) These plants still remain without increase: but young plants may be obtained in some of the nurseries, which have been raised from seeds; and at Vienna, as we are informed by Mr. Charles Rauch, it succeeds perfectly by budding on the common dog rose. Sect. V. Po'MEE Lindl. GENUS XIII. CRATE GUS Lindl. THE THORN. Lin. Syst. Icosándria Di-Pentagýnia. Description, &c. The species are small deciduous trees or shrubs, mostly natives of Europe and North America, and some of them of Asia and the north of Africa. One of them, the common hawthorn, is well known, throughout the middle and north of Europe, as a hedge plant. The species all flower and fruit freely; and the wood of all of them is hard and durable, and the plants of considerable longevity. Almost all the flowers are white, and the fruit is generally red; though in some sorts it is yellow, purple, black, or green. All the species ripen fruit in the neighbourhood of London, most of them abundantly; by which, or by grafting, they are generally propagated. When the species, which have naturally a dwarf habit of growth, are intended to assumie the character of low trees, they are grafted standard high upon C. Oxyacántha, C. coccínea, or on some other of the strong-growing kinds; in consequence of which practice, this genus furnishes a greater number of handsome small trees for ornamental grounds than any other ligneous family whatever. All the species will grow on any soil that is tolerably dry; but they will not grow vigorously in a soil that is not deep and free, and rich rather than poor. Whether as small trees or as shrubs, they are all admirably adapted for planting grounds of limited extent; and especially for small gardens in the neighbourhood of large towns. They are not only highly beautiful when in flower (a period which extends from the beginning of April to the end of July, commencing with C. purpùrea, and ending with C. cordata), but also when they are covered with ripe fruit, which includes a period commencing with C. purpùrea and C. nìgra, in the beginning of July, and continuing till the following spring or summer; C. mexicana, C. virgínica, and some other species, retaining their fruit all the winter. Of all the genera of hardy deciduous ligneous plants in cultivation in British gardens, there is not one which, taking it altogether, can be compared with the genus Cratæ`gus. All the species may be trained either as small, handsome, exceedingly picturesque trees; or as beautiful and picturesque shrubs; at the pleasure of the cultivator. They have all a characteristic, neat, orderly manner of growth; neither so slow as to convey the idea of want of vigour, nor so rapid and robust as to be considered coarse and rambling. Their leaves are remarkably neatly cut, and finely tufted; their flowers appear in masses so abundant, in some species, as almost to cover the plant in the flowering season; and their fruit is produced in as great abundance as their flowers. The colour of the flowers is generally white, and they are mostly more or less fragrant; some of them, as the common hawthorn, being particularly so: their colour, though white at first, yet in some cases, as in that of the common double-flowered hawthorn, dies off of a very fine pink; and there are several pink flowered varieties of the common hawthorn which are strikingly ornamental. The fruit varies in size, from that of C. spathulata, which is not much larger than a mustard seed, to that of C. mexicana, which is about as large as a golden pippin apple. The colour of the fruit, as already mentioned, is red, yellow, black, or green, and includes many varieties of shade. The fruit of several species, such as C. Azaròlus, C. Arònia, C. odoratíssima, and C. tanacetifòlia, are agreeable to the palate; and those of all the species are greedily devoured by singing birds of many kinds, especially the thrush family. Wherever, therefore, it is desirable to encourage singing birds, both as such, and for the good they do in keeping down insects, the genus Cratæ gus ought to be planted. All the species and varieties are exceedingly hardy; and, if there were a demand for them, they might be propagated in as great numbers as the common hawthorn. Most of the species would make excellent hedges; and, were it only the practice, in planting hedges along the sides of the public highways, to introduce here and there, as standards, thirty or forty sorts, which might be raised from seed, the ornament to the country would be such as those only can form an idea of who have seen the collections of Crataegus at White Knights near Reading, or at Courset near Boulogne, when the trees are in flower, and when they are in fruit. Finally, if a man were to be exiled to an estate without a single tree or shrub on it, with permission to choose only one genus of ligneous plants to form all his plantations, shrubberies, orchards, and flower-gardens, where would he find |