The flowers are eaten by the hill people, and formed into a jelly by European visiters. The leaves of R. campanulatum, being used as a snuff by the natives of India, are imported from Cashmere, under the names of hoolas-kasmeeree (Cashmere snuff) and burg-i-tibbut (Thibet leaf), though easily procurable within the British territories. It is remarkable that De Candolle mentions the employment in the United States, for a similar purpose, of the brown dust which adheres to the petioles of kalmias and rhododendrons. The leaves of R. lepidòtum (a species not yet introduced into Europe) are highly fragrant, and of a stimulant nature." (Illust., p. 219.) The culture of all the species is nearly the same: they all require peat earth, or, at least, thrive best in it; and some of them will not live without it. They may all be propagated by cuttings of the growing shoots, planted in fine sand, and covered with a glass, or by layers; but the best plants of all the species are procured from seed. The varieties can, of course, only be continued by cuttings or layers; and the stools for these require to be planted in beds of peat, which should be kept tolerably moist. The seeds, if ripened in this country, should be sown soon after gathering; and those imported from America, immediately on being received; because, though the seeds of all the Ericàcea will retain the vital principle for several years (see p. 1100.), yet the longer they are kept out of the soil, the less likely they are to germinate, and the greater will be the risk of losing some of them. They should be sown in pots or boxes, or in a border shaded from the direct influence of the sun; and kept in a uniform state of moisture, and protected from the frost. In sowing, the surface of the soil should previously be made quite smooth, and gently pressed down, or watered till it has settled to a level surface; and, after the seeds have been equally distributed over this surface, they should be covered with no more soil than is barely requisite to conceal them from the eye. Seeds sown in autumn will germinate in the following spring, and be fit for transplanting into nursery lines or pots by the autumn, or by the spring of the following year. These directions will apply generally to all the species, but are more particularly applicable to those which are perfectly hardy. The culture of the half-hardy sorts will be noticed after describing them. GENUS XX. RHODODENDRON L. THE RHODODENDRON, or ROSE BAY. Lin. Syst. Penta-Decandria Monogynia. Identification. Lin. Gen., No. 548.; Schreb. Gen., No. 746.; Gærtn. Fruct, 1. p. 304. t. 63.; Juss. Gen., 158.; D. Don in Edinb. Phil. Journ.; Prod. Fl. Nep., p. 152.; Don's Mill., 3. p. 843. Synonymes. Azalea sp. of authors; Rhodora Lin.; Chamarhododendros Tourn. Inst., t. 575.; Rhododendron, Fr., Ital., and Span.; Alpbalsam, Ĝer. Derivation. From rhodon, a rose, and dendron, a tree; in reference to the terminal bunches of flowers, which are usually red, or rose-colour. Description, &c. Shrubs or trees, usually evergreen, but in the Azalea division almost entirely deciduous, with quite entire alternate leaves, terminated by a withered tip, or yellow gland; and terminal, corymbose, showy flowers. Cultivated in sandy peat, kept rather moist, and propagated by layers, seeds, or cuttings. Under this genus Professor D. Don has included the Azalea, which, however technically correct, appears to us injudicious in a practical point of view; and, though we have followed his arrangement in this article, yet we have indicated two sections, containing the Indian or tender, and the Asiatic and American or hardy, azaleas, which those who cultivate extensive collections of these shrubs may, if they choose, consider as constituting the genus Azalea as heretofore. Such persons, therefore, may view the genus Azalea as remaining exactly as it is in our Hortus Britannicus. i. Ponticum D. Don. Sect. Char. Limb of calyx short, 5-lobed. Corolla campanulate. Stamens 10. Ovarium 5-celled. Leaves coriaceous, evergreen. (Don's Mill., iii. p. 843.) 1. R. PO'NTICUM L. The Pontic Rhododendron, or Rose Bay. Identification. Lin. Sp., 562.; Don's Mill, 3. p. 843.; Lodd. Cat., ed. 1836., Engravings. Pall. Fl. Ross., 1. p. 43. t. 29.; Jacq. Icon. Rar., 1. t. 78.; Lam. Ill., t. 364.; Bot. Mag., t. 650.; and our fig. 931. Spec. Char., &c. Leaves oblong-lanceolate, glabrous on both surfaces, attenuated towards the thick petioles, with a streak on the upper surface, of a wide lanceolate form. Racemes short, corymbose. Leaves sometimes becoming ferruginous beneath. Corolla purple, or purplish pink, large; with ovate, acute, or lanceolate segments. Calyx minute, 5-toothed, somewhat cartilaginous. (Don's Mill., iii. p. 843.) An evergreen shrub; a native of Pontus (now Armenia), in Asia Minor, where it grows to the height of 10 ft. or 12 ft.; flowering in May and June. It was introduced in 1763, and is frequent in British gardens. Varieties. R. p. 2 obtùsum Wats. Dend. Brit., t. 162., Don's Mill., iii. p. 843., R. p. 4 Smithii Swt. Brit. Fl.-Gard., n. s., t. 50., Don's Mill., iii. p. 843., R. p. 6 azaleoides; R. azaleöìdes Desf.; R. p. 8 subdecíduum Andr. Bot. Rep., t. 379., Hayn. Abbild., t. 15.; is a hybrid between R. pónticum and some species of Azalea, with fragrant blossoms. It was originated about 1820, and is a favourite in collections. There is a subvariety, R. p. a. 2 odoratum Lodd. Cat., in which the flowers are supposed to be more odoriferous than in R. p. azaleöìdes. Nursery Varieties. The following are cultivated by Messrs. Loddiges. (Catalogue of Plants, &c., at Hackney, 16th ed., 1836.) R. p. álbum. angustifolium. bromeliafolium bullatum. cassinef dlium. R. p. fl. plèno. kalmiæ folium. R. p. macrophyllum. roseum. spectabile. violaceum. Description. The Rhododendron pónticum is the commonest species of the genus in British gardens, where it grows to the height of from 5 ft. to 15 ft., or upwards; forming a dense bush, which will spread over a large space, if it be allowed abundance of room. The branches are round, with a rather testaceous bark, marked by scars. The leaves are long, coriaceous, quite entire, smooth and shining above, and somewhat ferruginous beneath. The flower buds are large and terminal, and the corollas of a fine purple. The seeds are small, and of irregular shape, like minute sawdust. In proper soil, if kept moist, the plant will make shoots, when young, of 1 ft. or more in length in a season, attaining the height of 4 ft. or 5 ft. in 5 or 6 years: but afterwards it grows more slowly; and, when a large bush, seldom makes shoots above 6 in. in length. It appears to be of considerable durability. Geography. The Rhododendron pónticum is a native of the Levant, in various places; of Georgia, Caucasus, and the Himalayas, and various other parts of Asia; but not of North America, unless R. purpureum and R. catawbiénse be varieties of this species, which may very possibly be the case. According to Pallas, this shrub is found nowhere in Russia, except in the southern calcareous district of Caucasus, where it grows in humid situations, along with the beech and the alder. Like all hair-rooted plants, it is generally found, in a wild state, in soft or minutely divided soil, but not always in soil analogous to our peat. It is often found on clayey loam, but it is only when this is kept moist, by being in a shady situation. On mountains, it never ascends so high as to approach the line of perpetual snow. History. The rhododendron was well known to the Greeks, both by that name, and by the name of rhododaphne, or the rose laurel. The Romans also were acquainted with this shrub; but, as Pliny observes, they had not the good fortune to give a name to it; for it was in ancient Italy, as it is at present throughout Europe, known principally by its original Greek name. The ancients were well acquainted with the poisonous qualities of the flowers of the rhododendron and azalea, both of which are abundant in Pontus; and the flowers had such an influence on the honey of the country, that the Romans would not receive it in tribute, but obliged the inhabitants of that part of Pontus to pay them a double portion of wax in lieu of it. Both the rhododendron and the azalea were abundant in the neighbourhood of Trebisond, in the time of Xenophon, and they still are so. Xenophon reports that, when the army of 10,000 Greeks, in their celebrated retreat, approached that city, his soldiers, having eaten the honey which they found in the environs, were seized with a violent vomiting and purging, followed by a species of delirium, so severe, that those least affected resembled drunken persons, and the others madmen. The ground was strewed about with the bodies of the soldiers, as it is after a battle. Nobody died, however, and the malady disappeared 24 hours after it had commenced, leaving only a sensation of great weakness. Turner, in his Herbal, must have had this story in view, when, in 1568, he wrote the following passage: "I have sene thys tre (the rhododaphne) in diverse places of Italy; but I care not if it neuer com into England, seyng it in all poyntes is lyke a Pharesy; that is, beauteus without, and within a rauenus wolf and murderer." It is possible, however, that Dr. Turner may have referred to the oleander, to which, as appears by Gerard (edit. 1636, p. 1406.), the names of rhododendron, rhododaphne, nerium, and oleander were at that time applied. The poisonous properties of the flowers of the R. pónticum are denied by Güldenstadt, and also by Pallas; both these authors asserting that it was the honey from the flowers of Azalea póntica (which grows plentifully among the bushes of the R. pónticum) that produced the deleterious effect on Xenophon's soldiers; it having been found, in modern times, that honey made from the flowers of this shrub, taken in large quantities, is highly deleterious. R. pónticum (as we have seen, p. 83.) was first introduced by Conrad Loddiges, in 1763; and it has since spread through the country with such an extraordinary degree of rapidity; that there is now scarcely a shrubbery or pleasure-ground in Britain without it. Properties and Uses. In its native country, we are not aware that this plant is applied to any use, except that to which all woody plants are applicable; viz. of being cut down for fuel. In Britain, it is planted as an ornamental shrub, not only in open situations, but, on a large scale, in woods, to serve as undergrowth, and as a shelter for game. Professor Henslow, in a communication to the Magazine of Natural History, vol. ix. p. 476., mentions that he had seen some crystals of a substance resembling sugarcandy, which were found in the decaying flowers of the R. pónticum. The syrup, which afterwards hardened into these crystals, always exuded "from the upper surface of the thickened base upon which the ovary is seated, and apparently from a minute glandular spot placed between the sinus formed by the two upper teeth of the calyx." The plant was in a morbid state, and the crystals were found more particularly within some of the flowers that had withered without fully expanding. In the Bulletin Universel, R. pónticum is stated to contain some grains of common sugar, of a pure white colour, on the surface of the upper division of the corolla. Soil, Situation, &c. It will grow in almost any soil; but, in England, it seems to thrive best in sandy peat, or deep sandy loam. In the common manured earth of gardens it succeeds worse than in unmanured loams of a close texture, even strong clays, particularly if the latter be kept moist. The want of tenacity of the manured garden soil alluded to, more especially in a dry season, seems not to allow it to cohere sufficiently to the small hair-like roots of this order of plants, to enable their very minute spongioles to imbibe nourishment from it. Propagation. All the rhododendrons may be propagated by cuttings of the young shoots, taken off in a growing state, when their lower ends have begun to ripen, and planted in pure sand, and covered with a bell-glass; but, in general, this mode is only worth adopting in the case of new and rare sorts. By layers, also, is a common mode with sorts which do not seed freely, or with particular varieties: but by far the most general method practised in gardens is by seeds. These are produced in abundance in this country; and they are also received from America. They are ripe in August and September; and, though they will retain their vegetative properties for upwards of a year, and some of them for several years, it is considered safest to sow them soon after they are gathered. The seeds should be sown in peat soil, or very fine sandy loam, in a shady border, or in pots; and treated as recommended at the head of this section. Culture. After seedling plants have been a year in pots, or in the seed-bed, they are transplanted into nursery lines, and removed every year, or every second year, and placed at greater distances, till they have attained the size at which it is considered desirable to sell them, or to plant them where they are finally to remain. At whatever age or size they are removed from the nursery, they require, in common with all hair-rooted plants, to have a small ball of soil attached to their roots, and to have these carefully protected from drought by mats. In consequence of almost all the rhododendrons and azaleas being removable with balls, they may be transplanted at any season of the year, though the autumn and spring are the periods generally made choice of. In consequence, also, of peat soil readily adhering to the fibrils of this genus, and, indeed, of all the Ericàceæ, it becomes less necessary to grow them in pots for the convenience of removal, than is the case with most other rare and valuable trees and shrubs: for example, the Magnoliacea. In some of the English nurseries, plants of Rhododendron pónticum are trained with single stems, to the height of 4 ft. or 5 ft., before they are suffered to branch off; and, so treated, they make very handsome small trees. Statistics. In the environs of London, some of the largest rhododendrons are in the arboretum at Kew, where they are nearly 12 ft. high. In the woods at Kenwood, there are also several of this height. At Wimbledon House, there is a bush, which, in 1834, was 33 ft. in diameter. In Hampshire, at Cuffhells, there is one which, in 1834, was 15 ft. high, and the branches covered a space 39 ft. in diameter. In Bedfordshire, at Woburn Abbey, in dry sand, without any bog or other ar. tificial soil, a plant, 20 years planted, in 1835 formed a bush 28 ft. in diameter. In Derbyshire, at Shipley Hall, there is a Rhododendron pónticum, which, in 1835, was 16 ft. high, the branches of which cover a space 56 ft. in diameter. In Scotland, at Minard, in Argyllshire, there is a plant 8 ft. high, which covers a space 20 ft. in circumference. In Ireland, at Oriel Temple, near Dublin, one, 60 years planted, was, in 1834, 16 ft. high, and covered a space 38 ft. in diameter. At Morn Park, near Cork, there is a plant which, in 10 years, is 94 ft. high, and the space covered by the branches is 22 ft. 6 in. in diameter. At Castle Freke, in the same county, there is one about the same size. Commercial Statistics. The price of plants of the species, in the London nurseries, is from 17. 5s. to 5l. per hundred; and of the varieties, from 1s. 6d. to 58. each; and seeds are 2s. per ounce. At Bollwyller, 2 years' seedlings are 25 francs per hundred, and the varieties from 1 franc to 2 francs each. At New York, plants of the species are 1 dollar each, and of the varieties 2 dollars. 2. R. MAXIMUM L. The largest Rhododendron, or American Rose Bay. Identification. Lin. Sp. Pl., p. 563.; Don's Mill., S. p. 843.; Lodd. Cat., ed. 1856. Engravings. Bot. Mag., t. 951.; Lam. Ill., 364.; Schmidt Baum., t. 121.; Mill. Icon., 229.; Catesb. Car,, S. t. 17. f. 2.; and our fig. 932. Spec. Char., &c. Arborescent. Leaves elliptic-oblong, acute, convex, bluntish at the base, whitish or rusty beneath, glabrous. Calycine segments oval-obtuse. Segments of corolla roundish. Flowers pale red, in umbellate corymbs, studded with green, yellow, or purple protuberances. (Don's Mill., iii. p. 843.) A native of North America, from Canada to Carolina, on the mountains, near rivulets and lakes, upon rocks and barren soils, where it continues flowering a great part of the summer; and where it forms a shrub growing to the height of from 10 ft. to 15 ft., flowering from June to August. Introduced in 1736, and frequent in collections. This species is not nearly so easy of culture as R. pónticum, and neither grows nor flowers so freely in British gardens. Though introduced by Peter Collinson in 1736, it did not flower in England till 1756, as Miller informs us; who adds, that the only person who then succeeded in raising it was Mr. James Gordon, at Mile End. The culture, &c., are the same as for R. pónticum. Plants of this species, in the London nurseries, are 1s, each, and seeds 3s. 6d. per oz.; at Bollwyller plants are 4 and 5 francs each; and at New York, from 50 cents to 1 dollar, and of the white variety 2 dollars. Varieties. 932 R. m. 2 álbum Hort. has pure white flowers, and is comparatively rare in British gardens. R. m. 3 hýbridum Hook. Bot. Mag., t. 3454.; R. fràgrans Hort.; R. hybridum Lodd. Cat.; is supposed to be a hybrid originated by fertilising the common white glaucous-leaved Azalea with the pollen of R. máximum. This variety has fragrant flowers, and, according to Sir W. J. Hooker, is " amply worthy of a place in every garden and shrubbery." 13. R. (M.) PURPUREUM G. Don. The purple-flowered Rhododendron, or American Rose Bay. Identification. Don's Mill, 3. p. 843. Synonymes. R. máximum purpureum Pursh Fl. Amer. Sept., 1. p. 297. R. ponticum macrophyllum Lodd. Cat. Spec. Char., &c. Arboreous. Leaves large, oblong-elliptic, flattish, acute, bluntish at the base, green, and glabrous on both surfaces. Segments of corolla oblong and obtuse. Flowers large, purple. Calycine segments obtuse. This shrub approaches near to R. ponticum; but it differs in its foliaceous calyx, and otherwise. It grows to an immense size; its stem being often found 18 in. and more in diameter; and its foliage triple the size of that of any other species. (Don's Mill., iii. p. 843.) It is a native of Virginia and Carolina, on the highest mountains, near lakes; where it forms a large shrub, or tree, growing to the height of 25 ft., flowering in May and June. This species appears to be in cultivation in some British nurseries, under the name of R. arboreum americànum; but in Messrs. Loddiges's |