THE ROCK-WALL IN SUN 17 



watching a number of the same kind one learns how 

 to judge them; one sees in Cerastium, for instance, 

 such as one of the many tufts hanging out of the 

 wall in the picture, that one tuft has a brighter and 

 better appearance than the next one. Then one sees 

 that the flower, which at first one had thought was 

 whiter than its neighbour, is not different in colour, 

 but has rather wider petals, and that they open more 

 and lie a little flatter, and that the leaf is somewhat 

 broader and its downy covering slightly heavier and 

 therefore whiter looking. 



Nothing is a better lesson in the knowledge of 

 plants than to sit down in front of them, and handle 

 them and look them over just as carefully as possible ; 

 and in no way can such study be more pleasantly or 

 conveniently carried on than by taking a light seat to 

 the rock- wall and giving plenty of time to each kind 

 of little plant, examining it closely and asking oneself, 

 and it, why this and why that. Especially if the first 

 glance shows two tufts, one with a better appearance 

 than the other ; not to stir from the place until one 

 has found out why and how it is done, and all about 

 it. Of course a friend who has already gone through 

 it all can help on the lesson more quickly, but I doubt 

 whether it is not best to do it all for oneself. 



Then the hanging plants, Cerastium, Afyssum, Aub- 

 rietia, Silene, Arabis, Gypsophila, Saponaria, Rock Pinks 

 and the like, though they grow quite happily on the 

 level, do not show their true habit as they do when 

 they are given the nearly upright wall out of which 

 they can hang. There are plenty of plants for the 



B 



