ROC [ 



thrive better if grown on the surface as 

 recommended for the Eschallot. In 

 other respects they are cultivated as 

 directed for Garlic. A very small bed 

 is sufficient for the supply of the 

 largest family. 



RO'CIIEA. (Named after La Roche, 

 a botanical author. Nat. ord., House- 

 leeks [Crassulaceas]. Linn., 5-Pentan- 

 dria 5-Peritagynid. Allied to Crassula.) 



Greenhouse evergreen succulents, from the 

 Cape of Good Hope. For culture see Crassula. 



It. ulbiflo'ra (white - flowered). White. July. 

 1800. 



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



June. 1810. 



biconve'xa (doubly-convex). . White. July. 



1823. 



capita' ta (headed). White. July. 1822. 



cocci'nea (scarlet). 1. Scarlet. July. 1710. 

 flo're-a'lbo (white- flowering). 1. 



White. July. 1811. 



cymo'sa (cymed). $. Red. August. 1800. 

 falca'ta (sickle- leaved). 3, Scarlet. July. 



1795. 



fln'va (yellow). Yellow, June. 1802. 

 jasmi'nea (Jasmine-like). i ! . White. April. 



1815. 



me'dia (mediate). 1. Red. June. 1810. 



perfolia'ta (leaf-steni-pierced). 4. Scarlet. 



July. 1700. 



albiflo'ra (white flowering). 4. 



White. July. 1800. 



odorati'ssima (sweetest-scented). 1. Pink. 



June. 1793. 



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



May. 1817, 



ROCKET. He'speris. 



ROCKET LARKSPUB. Delphinium 

 aja'cis. 



ROCK LYCHNIS. Visca'ria. 



ROCK ROSE. Ci'stus. 



ROCK-WORK is one of the most dim- 

 cult 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 j 

 hand plenty of large rough stones, j 

 broken bricks, or stony rubbish of any ; 

 kind or colour, proceed with these to 

 imitate the form of natural rock as i 

 nearly as possible. Rough, bold, angu- 

 lar projections, and deeply-formed 

 chasms, are the principal features in > 

 natural scenery which please us most. 

 A rock, with a. flat unbroken surface, , 

 whether horizontal or perpendicular, j 



f82 ] ROC 



i presents too much sameness to be 

 | pleasing to the eye : therefore, in iini- 

 < tating nature, the projections should be 

 varied and bold, and unless ragged- 

 ness and intricacy form principal fea- 

 i tures in its composition, it will lose 

 i, much of its effect. If the rock-work 

 j be on a large scale, it should not be 

 one continued line, but broken at in- 

 I tervals, in one part lost beneath the 

 ; surface of the earth, and again rising 

 | in another part and resuming its sinu- 

 ; ous form. 



So far there is little difference be- 

 tween 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 intended for the plants 

 which are to cover the rock, must be 

 left open, so that the roots may pene- 

 trate to the soil beneath the stones. 

 The next operation is to daub the whole 

 mass over with Roman cement. For 

 this purpose the latter should be 

 mixed with water until it is of the con- 

 sistence of thick paint, in which state 

 it may be applied to the stones with a 

 large painter's brush. The spaces 

 between 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 comparison far more natural than 

 that made in the usual way. It has 

 none of that disjointed appearance 

 which usually accompanies rock-work 

 made without cement. After a few 

 month's 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 promi- 

 nent parts. If the cement be of a 

 colour too light, which, for some situa- 

 tions, 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* 



