R. RACEMOSUM.--Central China, 1880. A neat little species, of dwarf, compact growth, from the Yunnan district of China. The flowers are pale pink edged with a deeper tint, about an inch across, and borne in terminal and axillary clusters. It has stood unharmed for several years in southern England, so may be regarded as at least fairly hardy. Its neat dwarf growth, and flowering as it does when hardly a foot high, renders it a choice subject for the Alpine garden. R. RHODORA (_syn Rhodora canadensis_).--North America, 1767. In general aspect this shrub resembles an Azalea, but it comes into flower long even before R. molle. Being deciduous, and producing its pretty purplish sweet-scented flowers in early spring, gives to the plant a particular value for gardening purposes, clumps of the shrub being most effective at the very time when flowers are at their scarcest. It thrives well in any peaty soil, and is quite hardy. R. VISCOSUM (_syn Azalea viscosa_).--Clammy Azalea, or Swamp Honeysuckle. North America, 1734. This is one of the hardiest, most floriferous, and easily managed of the family. The white or rose and deliciously fragrant flowers are produced in great abundance, and impart when at their best quite a charm to the shrub. It delights in rather moist, peaty soil, and grows all the stronger and flowers all the more freely when surrounded by rising ground or tall trees at considerable distance away. The variety R. viscosum glaucum has leaves paler than those of the species; and R. viscosum nitidum, of dwarf, compact growth, has leaves deep green on both sides. R. WILSONI, a cross between R. ciliatum and R. glaucum, is of remarkably neat growth, and worthy of cultivation where small-sized kinds are a desideratum. The following Himalayan species have been found to thrive well in the warmer parts of England, and in close proximity to the sea;--R. argenteum, R. arboreum, R. Aucklandii, R. barbatum, R. ciliatum, R. campanulatum, R. cinnabarinum, R. Campbelli, R. compylocarpum, R. eximium, R. Fortunei, R. Falconeri, R. glaucum, R. Hodgsoni, R. lanatum, R. niveum, R. Roylei, R. Thompsoni, and R. Wallichii. R. Ungernii and R. Smirnowii, from the Armenian frontier, are also worthy of culture, but they are at present rare in cultivation in this country. Few hardy shrubs, it must be admitted, are more beautiful than these Rhododendrons, none flowering more freely or lasting longer in bloom. Their requirements are by no means hard to meet, light, peaty soil, or even good sandy loam, with a small admixture of decayed vegetable matter, suiting them well. Lime in any form must, however, be kept away both from Azaleas and Rhododendrons. They like a quiet, still place, where a fair amount of moisture is present in the air and soil. HARDY HYBRID RHODODENDRONS.