R. CHRYSANTHUM is a Siberian species (1796) of very dwarf, compact growth, with linear-lanceolate leaves that are ferruginous on the under side, and beautiful golden-yellow flowers an inch in diameter. It is a desirable but scarce species. R. COLLETTIANUM is an Afghanistan species, and one that may be reckoned upon as being perfectly hardy. It is of very dwarf habit, and bears an abundance of small white and faintly fragrant flowers. For planting on rockwork it is a valuable species. R. DAHURICUM.--Dahuria, 1780. A small-growing, scraggy-looking species of about a yard high, with oval-oblong leaves that are rusty-tomentose on the under sides. The flowers, which are produced in February, are purple or violet, in twos or threes, and usually appear before the leaves. It is a sparsely-leaved species, and of greatest value on account of the flowers being produced so early in the season. One of the hardiest species in cultivation. R. dahuricum atro-virens is a beautiful and worthy variety because nearly evergreen. R. FERRUGINEUM.--Alpine Rose. Europe, 1752. This dwarf species, rarely exceeding a yard in height, occurs in abundance on the Swiss Alps, and generally where few other plants are to be found. It is a neat little compact shrub, with oblong-lanceolate leaves that are rusty-scaly on the under sides, and has terminal clusters of rosy-red flowers. R. FLAVUM (_syn Azalea pontica_).--Pontic Azalea. A native of Asia Minor (1793), is probably the commonest of the recognised species, and may frequently, in this country, be seen forming good round bushes of 6 feet in height, with hairy lanceolate leaves, and large yellow flowers, though in this latter it varies considerably, orange, and orange tinged with red, being colours often present. It is of free growth in any good light peaty or sandy soil. R. HIRSUTUM.--Alpine Rose. South Europe, 1656. Very near R. ferrugincum, but having ciliated leaves, with glands on both sides. R. hallense and R. hirsutiforme are intermediate forms of a natural cross between R. hirsutum and R. ferrugincum. They are handsome, small-growing, brightly flowered plants, and worthy of culture. R. INDICUM.--Indian Azalea. A native of China (1808), and perfectly hardy in the more favoured portions of southern England, where it looks healthy and happy out of doors, and blooms freely from year to year. This is the evergreen so-called Azalea that is so commonly cultivated in greenhouses, with long hirsute leaves, and large showy flowers. R. indicum amoenum (_syn Azalea amoena_), as a greenhouse plant is common enough, but except in the South of England and Ireland it is not sufficiently hardy to withstand severe frost. The flowers are, moreover, not very showy, at least when compared with some of the newer forms, being dull magenta, and rather lax of habit.