PART I.] 



CULTURAL 



Lychnis and smne in 



Viscaria and Silene acaulis, form long tap roots, thrive 



well in such fissures, provided the earth in the fissure is 



continuous, and leads 'backward to a sufficient 



lody of soil. Where the horizontal fissures 



are very narrow, owing to the main rocks 



being in contact in places, and leaving 



only irregular and interrupted fissures, such 



plants as Lychnis Lagascce, Lychnis pyrenaica, 



and others, bearing and preferring hot sunny 



exposures, do well. But many plants that 



would bear the heat and drought, if they 



could get their roots far enough back, 



would quickly die if placed in such fissures, from the want 



of soil and moisture near the front; therefore it is usually 



better, in building rockwork with these fissures, to keep 



the main rocks slightly apart by 



means of pieces of very hard stone 



(basalt, close-grained ' flag,' etc.), so 



as to leave room for a good inter- 



mediate layer of rich loam, stones, 



or grit, mingled with a little peat. The front view of such a 



structure would be as above the dark spaces being firmly 



filled with the appropriate mixture of soil lefore the upper 



course of large rocks is placed. 



" As a rule, oblique and vertical fissures are both preferable 

 to horizontal ones ; but care should be taken with ' oblique 

 fissures that the upper rock does not overhang. A plant placed 

 at J will often die, when the same placed at H will live, because 



Horizontal Fissure. 



Right 



Wrong. 



the rain falling on the sloping face of rock at I will drop of at J, 

 and miss the fissure J altogether, while that falling on the slop- 



