Cosmea Bipinnata.--A very pretty half-hardy annual which flowers in July. Sow the seed early in spring on a slight hotbed covered with glass, and transplant to the flower border at the end of May. Height, 2 ft. Cosmos.--Pretty plants, the flowers resembling a single Dahlia. They are mostly hardy, but some need protection. The annuals should be raised on a hotbed in February and be planted out in May. The perennials, too, are brought forward in heat. Some flower in June, others in September. Height, 1 ft. to 3 ft. Cotoneaster.--Evergreen shrubs which will grow in any soil and are easily increased by layers. C. Hookeriana attains the dimensions of small trees, and produces a profusion of white flowers and bright crimson berries. C. Simonsii is largely used as a hedge. Height, 6 ft. to 8 ft. C. Rupestris is a small-leaved, prostrate perennial species, bearing white flowers from May to August, followed by red berries. Height, 3 in. Cotyledon Chrysantha (_Umbilicus)._--A choice Alpine succulent which thrives in a sandy loam, or in well-drained pots of the same soil. It flowers from May to August, and is multiplied by cuttings, which must be left to dry for a few days in a sunny place. Flowers are produced from May to August. Height, 3 in. Cowslips.--Well-known hardy perennials. These require the same treatment as Primulas. Plant in a mixture of loam and peat, and divide as soon as the bloom has died off. Height, 6 in. Cowslips, Cape.--_See_ "Lachenalia." Crambe Cordifolia (_Tournefort, or Sea Cabbage_).--This hardy herbaceous plant is suitable for a wild garden. It likes a good, rich soil, and is easily increased by seed or division. August is its flowering period. Height, 3 ft. Crane's Bill.--_See_ "Geranium Argentium." Crataegus Pyracantha (_Fire Thorn_).--This hardy, ornamental shrub will grow in any soil. It should be planted early in spring on a south or south-west wall, and may be increased by seeds, by budding, or by grafting. The profuse brilliant orange-coloured berries of the C. Lelandii (Mespilus) ensures it a place on walls and trellises. A sunny position gives best results. Prune in March. Creeping Jenny.--_See_ "Lysimachia Nummularia." Crepis (_Hawkweed_).--An interesting hardy annual. It merely requires sowing in spring, and will grow in any soil. The flowers are produced in June. Height, 1 ft. Cress.--Sow at intervals of a week from March to September in the open ground, and during the winter months in frames. A shady position is most suitable. By these frequent sowings, and by often cutting over such as readily renew a bottom growth, a constant succession of tender shoots is obtained.