Sternbergia Lutea.--A hardy perennial which produces bright yellow flowers in August. It likes a rich soil, and is propagated by off-sets. Height, 6 in. Stipa Pennata (_Feather Grass_).--One of the most graceful of our ornamental grasses, and most attractive in the border. The seed may be sown early in March, keeping the ground moist until it has germinated, and it is also increased by division. Height, 2 ft. Stobæa Purpurea.--A hardy border plant with long spiny foliage, and bearing from July to September large light blue flowers. It requires a light, rich soil. Young cuttings may be struck in sand. Height, 1 ft. Stocks-- _ANNUAL, OR TEN WEEKS' STOCKS_.--Sow the seeds in February, March, April, and May for succession; those sown in May will continue to flower till Christmas. The soil should be rich, and occasionally a little manure-water may be given. Another sowing may be made in August and September. When the plants have several leaves pot off singly in vegetable loam and river sand. Height, 1 ft. to 1-1/2 ft. _BROMPTON_.--Sow very thinly during the first week in May in a rich, light, sandy border, with an eastern aspect. When 2 or 3 in. high, thin out to 9 in. apart. Those taken out may be re-planted in the flower border, 9 in. from each other. In transplanting reject those plants having a long tap-root: they generally prove to be single. If the following winter be severe they must be protected with mats. Any desirable varieties may be propagated by cuttings, which root readily under glass if kept shaded. Should it be desirable to transplant them to another part of the garden, March or April will be found the best time to remove them. Shade the plants till they are established, and use liquid manure till they begin to flower. _GREENHOUSE OR SHRUBBY_ species grow best in a mixture of light soil and sand, and cuttings of these Stocks root readily under glass. _NIGHT-SCENTED STOCKS_.--_See_ "Mathiola Bicornis." If Emperor, Imperial, or Intermediate Stocks are sown in March or April, they will flower in the autumn; if sown in June or July they will flower during the following June, and throughout the summer and autumn. Stokesia Cyanea.--A handsome herbaceous perennial which is quite hardy, but owing to the late period at which it flowers its blooms are liable to be cut off by frosts. It is therefore more suitable for a cool house than the open air, unless the warmest and most sheltered position be assigned to it. A rich, sandy soil is indispensable for its growth. It may be increased by dividing the roots in spring. The flowers are produced from October to December. Height, 1-1/2 ft. Stonecrop.--_See_ "Sedum."