C. LAURIFOLIUS.—­Laurel-leaved Cistus.  Spain, 1731.  This is the hardiest species in cultivation, but, like the latter, is favourable to the milder parts of these islands, and especially maritime districts.  Frequently it rises to 7 feet in height, and is then an object of great beauty, the large yellowish-white flowers showing well above the deep green Laurel-like leaves.

C. MONSPELIENSIS (South of Europe, 1656), and its variety C. monspeliensis florentinus, the former with white, and the latter with white and yellow flowers, are fairly hardy in the milder parts of Britain, but cannot be recommended for general planting.

C. PURPUREUS.—­Purple-flowered Cistas.  In this species, which may rank next to the latter in point of hardihood, the flowers are of a deep reddish-purple, and with a darker blotch at the base of each petal.

C. SALVIFOLIUS is of loose and rather untidy growth, with rugose leaves and white flowers.  It is very variable in character, and the form generally cultivated grows about 4 feet high, and has ovate-lanceolate, almost glabrous leaves.

Other species that are occasionally to be found in collections are C. creticus, with yellow and purple flowers; C. hirsutus, white with yellow blotches at the base of the petals; and C. Clusii, with very large pure-white flowers.  All the species of Gum Cistus, or Rock Rose as they are very appropriately named, will be found to succeed best when planted in exalted positions, and among light, though rich, strong soil.  They are easy of propagation.

CITRUS.

CITRUS TRIFOLIATA.—­Japan, 1869.  This is a singular low-growing shrub, with ternate leaves, spiny branches, and fragrant white flowers.  It is hardy in many English situations, but does not fruit freely, although the orange-blossom-like flowers are produced very abundantly.  A pretty little glossy-leaved shrub that is well worthy of attention, particularly where a cosy corner can be put aside for its cultivation.

CLADRASTIS.

CLADRASTIS AMURENSIS.—­Amoor Yellow Wood.  Amur, 1880.  This is a shrub that is sure to be extensively cultivated when better known, and more readily procured.  It has stood uninjured for several years in various parts of England, so that its hardihood may be taken for granted.  The pretty olive-green of the bark, and the greyish-green of the leathery leaves, render the shrub one of interest even in a flowerless state.  In July and August the dense spikes of white, or rather yellowish-white flowers are produced freely, and that, too, even before the shrub has attained to a height of 2 feet.  It is well worthy of extended culture.

C. TINCTORIA (syn C. lutea and Virgilia lutea).—­Yellow Wood.  North America, 1812.  This is a handsome deciduous tree that does well in many parts of the country, and is valued for the rich profusion of white flowers produced, and which are well set-off by the finely-cut pinnate leaves.  It is a valuable tree for park and lawn planting, requiring a warm, dry soil, and sunny situation—­conditions under which the wood becomes well-ripened, and the flowers more freely produced.