56 THE STORY OF MY ROCK GARDEN 



arachnoideum, and its larger form Laggeri (see page 24) 

 are especial favourites with me, the silky " cob web " 

 which covers them, especially the newer growth, is very 

 attractive in summer, when contrasted with their 

 intensely bright red flowers. The reason for this 

 curious protection puzzled me for a long while, but the 

 explanation generally accepted is, I believe, that it 

 moderates the intense heat of the sun as it pours down 

 on the mountain sides in Switzerland, where this little 

 plant grows in very exposed places, and protects the 

 soft tissue of the infant leaves, which otherwise might 

 be damaged. 



There is another large class of plants which can be 

 used with very considerable effect in the Alpine garden, 

 and which I have hardly referred to yet namely, plants 

 with silvery foliage. A large amount of the beauty of 

 an Alpine garden depends upon the judicious use of 

 such plants. Much can be done to emphasise a pro- 

 monotory or direct the eye to any desired point of the 

 garden by the careful use of Cerastium alpinum var. 

 lanatum, some of the white foliaged Dianthi, such as 

 D.+ ccesius, Erodium chrysanthum, several of the 

 Achilleas, and planted in some crevice, in poor, gritty 

 soil, that lovely little Potentilla nitida, and its variety 

 alba. 



A particularly decorative member of this grovip is 

 Artemisia vallesiaca, illustrated opposite. On some 



