Propagated by seeds, suckers, layers or cuttings. Grafting and budding are each practicable, and are adopted when growing tall standards or scarce varieties. The seed of all should be sown as soon as gathered, or stored in sand till the following spring. All superior varieties should be increased by suckers or layers. Stools kept for layering must be allowed to make more growth than those used for suckers. Free growth must be encouraged for a year or more, and, any suitable time in winter, the shoots should be bent to the ground, pegged firmly, and covered to the depth of three inches with earth. They will be well-rooted by the following autumn, and may then be removed and planted out permanently. =Corynostylis=, Calyptrion. _Violarieæ._ Increased by seeds, or by cuttings of the young wood, placed in sand in bottom heat, under glass. =Cosmos.= _Compositæ._ Seeds, usually started under glass. The tuberiferous species, like Dahlia, which see. =Costus.= _Scitamineæ._ Increased by dividing the roots. =Cotoneaster.= _Rosaceæ._ Propagated readily by seed, which should be sown in spring; by layers or cuttings in autumn, or by grafting on _C. vulgaris_, the common quince, or the hawthorn. =Cotton= (_Gossypium_). _Malvaceæ._ Seeds commonly. Grown as a curiosity under glass; it may be increased by soft cuttings. =Cotyledon= (Navelwort). _Crassulaceæ._ Increased by seed, offsets, cuttings of the stem, and by leaves. The leaves should be pulled off in autumn, laid on dry sand in pans on a shelf in a propagating or other warm house, and not watered until small plants appear at the ends of the leaves. =Cowslip.= See Primula. =Crambe.= _Cruciferæ._ Increased by seeds, by dividing the roots and by root-cuttings. See Sea-kale. =Cranberry= (_Vaccinium macrocarpon_). _Ericaceæ._ The cultivated cranberry is propagated entirely by cuttings. These are made from vigorous young runners, from six to ten inches in length, and they are thrust obliquely into the soil until only an inch or two of the tip projects. Some blunt instrument, as a stick, is commonly used to force them into the sand of cranberry bogs. Planting is done in the spring, and the cuttings are taken just previous to the operation. If cranberry seedlings are desired, the seeds should be sown in flats of peaty earth, which are stored until spring in some protected place, in the manner of stratification boxes. The seeds should be covered lightly, preferably with fine moss. The plants are allowed to grow the first year in the box. =Crassula.= _Crassulaceæ._ Seeds; also by cuttings, which should be taken off and laid for two or three days in the sun to dry before planting. =Cratægus= (Haw, Hawthorn). _Rosaceæ._