Crown Imperials.—­See “Fritillarias.”

Crucianella Stylosa.—­A hardy perennial.  Sow in August or September in a sheltered spot to stand the winter.  The seed may also be sown from March to midsummer, and the plants moved in autumn to the place where they are to bloom.  Their delicate pink flowers are produced in July.  Height, 1 ft.

Cuckoo Flower.—­See “Cardamine.”

Cucumbers.—­A rich, loamy soil is most suitable for their growth.  Sow frame varieties in a heat of 75 degrees or 85 degrees during February and March for summer use, and when the plants are of sufficient size transplant to a well-prepared hotbed.  Sow again in September for winter use.  The hardy or ridge cucumbers (which are not suited for frame or hothouse culture) should be raised in a frame or hot-bed in April, and planted out about the middle of May in a warm border on strawed ridges prepared with good stable manure, placing a hand-glass over each plant until it is well established.

Cunila Mariana (Dittany).—­This hardy perennial produces heads of pretty purple flowers from July to September.  It is not particular as to soil, and can easily be increased by division.  Height, 1 ft.

Cuphea.—­Shrubs of a rather pretty description.  The stove varieties require a sandy loam to grow in, and may be propagated by cuttings.  The annuals should be sown on a gentle hotbed, and when strong enough potted off and kept in the greenhouse; they should not be moved into the open before the end of May.  The perennial species if sown early make good bedding plants the first year; they need protection in the winter.

Currants.—­Black.—­A rich, deep soil and a moist situation, together with partial shade, are most suitable for their growth.  They succeed better as bushes than as espaliers or trained to walls.  Cuttings of the previous year’s growth are taken in autumn and planted firmly 1 ft. by 6 in. apart.  In two years shift every alternate plant so as to allow room for expansion, and plant out finally to a distance of 5 ft.  In pruning the bushes, remember that the fruit is borne on the young wood, therefore only sufficient should be cut away to allow of the admission of air and sunshine and the further growth of young branches.  A portion of the old wood should be removed each year.  Mulch the roots, and keep the plants supplied with water in dry seasons.  Baldwin’s Black, Ogden’s Black, Black Naples, Lee’s Prolific, James’ Prolific, and Old Black are among the best.

Red and White.—­An open, sunny position is needed.  The soil that suits them best is a deeply-manured, stiff loam.  They are readily raised from cuttings—­which should be as long and strong as possible—­taken in autumn.  Cut away all the eyes except the three uppermost ones, and plant firmly in rows 1 ft. by 6 in. apart.  Transplant at the end of the second year to a distance of 5 ft. apart.  While the plants are young cut