ROC 



ROD 



Greenhouse evergreen succulents, from the 

 Cape of Good Hope. For culture, seeCaA'ssuLA.. 



R. albiflo'rn (white-flowred). White. July. 1800. 



bi'color (two-coloured). 1. Yellow, scarlet. 



June. 1810. 



biconvr.'xn ( doubly-con vex).;J. White. Ju<y.lS23. 



capita' tn (he*.l-:<l). White. July. 18:22. 



cocci'nna (scarlet). I. Scarlet. July. 1710. 

 flit'i-e-a'lk'* (white-flowering). I. White. 



July. 1311. 



cymo's'i (cvraed). $. Red. August. 1800. 

 fulcn'ta (ickle-/<Med). 3. Scarlet. July. 1795. 



fla!a (yellow). Yellow. June. 1802. 



'janminea (j ismine-like). . White. April. 1815. 



me'diu (rnrdiate). 1. R^d. June. 1810. 



perfolin'tit (leaf-stem-pierced). 4. Scarlet. July. 



1700. 



al/tiflo'ra (white-flowering). 4. White. 



Julv. 1SOO. 



odorati'gtima (sweetest-scented). l.Piak. June. 



1793- 



versi'color (changeable-coloured). 2. White. 



May. 1817. 



ROCKET. He'speris. 



ROCKET LARKSPUR. Delphi'nium oja'cls. 



ROCK LYCHNIS. Visca'ria. 



ROCK ROSE. Gi'stns. 



ROCK-WORK is one of the most difficult 

 things to construct tastefully. If the 

 body of the rock is intended to be raised 

 much above the ground level, a quantity 

 of soil and rubbish should be carried 

 into the centre of the space. This soil, 

 besides serving to support the rock- work, 

 will also form a border for the plants to 

 grow in. Having at hand plenty of large, 

 rough stones, broken bricks, or stony 

 rubbish of any kind or colour, proceed 

 with these to imitate the form of natural 

 rock as nearly as possible. Rough, bold, 

 angular projections, and deeply-formed 

 chasms, are the principal features iu 

 natural scenery which please us most. 

 A rock, with a flat unbroken surface, whe- 

 ther horizontal or perpendicular, presents 

 too much sameness to be pleasing to the 

 eye; therefore, in imitating nature, the 

 projections should be varied and bold, 

 and unless raggedness and intricacy form 

 principal features in its composition, it 

 will lose much of its effect. If the rock- 

 work be on a large scale, it should not 

 be one continued line, but broken at in- 

 tervals, in one part lost beneath the sur- 

 face of the earth, and again rising in an- 

 other part and resuming its sinuous form. 



So far there is little difference between 

 this and the common method of making 

 artificial rock. When, however, every 

 stone has been arranged to suit the eye, 

 the interstices between them are to be 

 filled up with any kind of rough mortar. 

 Of course, fissures, and similar places in- 



tended for the plants which are to cover 

 the rock, must be left open, so that the 

 roots may penetrate to the soil beneath 

 the stones. The next operation is to 

 daub the whole mass over with Roman 

 cement. For this pui'pose the latter 

 should be mixed with water until it is of 

 the consistence of thick paint, in which 

 state it may be applied to the stones with 

 a large painter's brush. The spaces be- 

 tween the stones having been filled with 

 rough mortar prevents the cement from 

 being wasted. The thickness of the 

 latter on the stones need not be more 

 than the eighth of an inch : it will unite 

 the whole into one mass ; and rock-work 

 thus constructed is, beyond all com- 

 parison, far more natural than that made 

 in the usual way. It has none of that 

 disjointed appearance which usually ac- 

 companies rock-work made without ce- 

 ment. After a few mouths' exposure to 

 the weather, rock- work thus formed (if 

 skilfully made) cannot, without careful 

 examination, be distinguished from a 

 natural mass; it will soon cover all but 

 the most prominent parts. If the cement 

 be of a colour too light, which, for some 

 situations may be the case, a little lamp- 

 black or soot may be mixed with it. 

 Care must, however, be taken that no 

 substance which may make the cement 

 more porous is used, otherwise it will 

 peel from the stones after a hard frost. 

 For the benefit of those who are not ac- 

 customed to using cement, we may men- 

 tion that no more should be moistened 

 at once than can be used in a short time. 

 If the cement be good it will quickly 

 harden, and will then be in a manner 

 useless. 



In making artificial rock for waterfalls , 

 or other constructions, where the cement 

 may be constantly exposed to the action 

 of the water, the best water-cement should 

 be u*ed. Any preparation that does not 

 quickly indurate under water will, in a 

 short time, be washed away, and leave 

 nothing but the bare stones. Wkatelcy. 



RODRIGUE'ZIA. (Named after E. Bod- 

 rignez, a Spanish botanist. Nat. ord., 

 Orchids [Orchidaceos]. Linn., 20-%- 

 nandria L-Monandria. ) 



Stove Brazilian orchids, cultivated in baskets. 

 See ORCHIDS. 

 R. Bi'rkeri (Barker's). 1. Green. January. 



cri'spa (curled). Green. 



lanceol'i'ta (spear - head - leaved). Yellow. 



March. Trinidad. 1821. 



laxiflo'ra (loose-flowered). . Pale green. 



