R. PONTICUM.--Pontic Rhododendron, or Rose Bay. Asia Minor, 1763. This
is the commonest species in cultivation, and although originally a
native of the district by the Black or Pontic Sea, is now naturalised
in many parts of Europe. It is the hardiest and least exacting of the
large flowered species, and is generally employed as a stock on which
to graft the less hardy kinds. Flowers, in the typical species, pale
purplish-violet and spotted. There is a great number of varieties,
including white, pink, scarlet, and double-flowering.

R. PONTICUM AZALEOIDES (_syn R. ponticum deciduum_), a hybrid between R.
ponticum and a hardy Azalea, is a sub-evergreen form, with a compact
habit of growth, and bearing loose heads of fragrant lavender-and-white
flowers. It is quite hardy at Kew.

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.