dra'ba. 



87 



DRAINING. 



fessor De Candolle's new name for 

 the common British species of Lo- 

 belia. It is an aquatic plant, and is 

 generally found in ponds, or small 

 lakes. There is an American species 

 of the same habits, and both have 

 blue flowers. 



Dorya'nthes. — Amaryllidacece — 

 D. excelsa, the only species known, 

 is a splendid Australian plant, send- 

 ing up a flower-stalk twenty or thirty 

 feet high, crowned with a head of 

 bright scarlet flowers. The plant is 

 herbaceous, and it requires a peaty 

 soil and green-house heat. It dies 

 as soon as it has produced its flowers* 



Doiiy'cnium. — Lp gumma see. — A 

 genus of little hardy plants, separated 

 by Tournefort from the Lotus, or 

 Bird's-foot Trefoil, and growing freely 

 in any common soil. They are most 

 suitable for rockwork. 



Double Dwarf Almond. (See 

 Cerasus.) 



Double Flowers are particularly 

 desirable to cultivate in gardens, not 

 only from their beauty, but from the 

 comparative certainty that exists of 

 their producing their flowers every 

 year, the plant not being weakened 

 by ripening seed. This is peculiarly 

 the case with the double-flowered 

 trees and shrubs ; the double-flowered 

 Peach, the double-flowered Cherry, 

 and the double-flowered Hawthorn 

 never failing to produce abundance of 

 blossoms every year so long as the 

 tree continues in health ; while the 

 single-flowered kinds generally fail in 

 producing an abundant crop of blos- 

 soms every second or third year. 

 This observation does not apply so 

 forcibly to semi-double flowers, as 

 they frequently ripen seeds. 



Dra v ba. — Cruciferee. — Willow- 

 grass. Very low plants, admirably 

 adapted for rockwork, as they are ge- 

 nerally found in a wild state in the 

 fissures and crevices of rocks and 

 mountains. They have generally 



white or yellow flowers, and should 

 be grown in sandy soil, on a bank, or 

 in any open situation, exposed to the 

 sun. 



Drac^'na. — Asphodelacece. — The 

 Dragon-tree. Eastern trees and shrubs 

 with the habit of palms. They re- 

 quire a stove in England, and to be 

 grown in peat and loam. The tooth- 

 brushes called Dragon's root, are 

 made from the root of the tree species 

 cut into pieces, about four inches 

 long ; each of which is beaten at one 

 end with a wooden mallet, to split 

 it into fibres. 



Dracoce'phalum. — Labiatce. — 

 Dragon's Head. Several species of 

 this genus are well known as garden 

 flowers ; particularly D. Moldivica, 

 the Moldavian Balm, a hardy annual, 

 and D. canariense, the Balm of 

 Gilead, a greenhouse shrub, which 

 should be grown in rich mould, and 

 is propagated by cuttings. Some of 

 the perennial species, such as D. 

 canescens, D . grandiflbrum (a native 

 of Siberia), and Z>. austriacum, have 

 large and splendid blue flowers ; all 

 these are quite hardy in any common 

 garden soil, and they are all propa- 

 gated by seeds or division of the 

 roots. 



Draining. — Draining in the open 

 garden is effected either by surface- 

 gutters, into which the water may 

 run, which does not sink into the 

 soil ; or by underground channels, 

 formed by earthenware tubes called 

 draining-tiles, or by tunnels built of 

 brick or stone, or by open drains 

 partially filled with small pebbles, 

 broken stones or bricks, or even by 

 faggots, branches of trees, or other 

 similar materials, which will preserve 

 a porous channel through which the 

 water may percolate. The draining- 

 tiles or other materials should not 

 rise nearer to the surface than the 

 common depth of dug ground, say 

 about a foot or eighteen inches ; and 



