202 ALPINE FLOWERS AND ROCK GARDENS. 



pratensis will be grown, but it is a pretty plant. The 

 double (flore pleno) may be preferred for garden 

 culture. *' Coral-root " is a large species familiar to 

 visitors to Switzerland. 



CERASTIUM (Snow-in-Summer).— Several refer- 

 ences have been made to this genus, in which it has been 

 spoken of as beautiful, both in foliage and bloom, but 

 as so rampant as to be a dangerous neighbour for choice 

 things. If the flower-lover can plant it on a high part 

 of the rockery, where it can have a clear run, he will 

 be able to enjoy its beauty to the full, and need harbour 

 no fears of ulterior mischief. The Cerastiums are very 

 accommodating plants. They make Hght of poor soil, 

 and will thrive in a thin layer of earth over chalk. After 

 being established a year they begin to spread rapidly, 

 and self-sown plants will appear in many parts of the 

 rockery. Some at least of these will have to be re- 

 moved, and if desired they can be transplanted and 

 used to form a broad margin. The fact that they 

 sow themselves in this way suggests that they are readily 

 raised from seed, and that it may be sown out of doors. 

 A strong plant will make such rapid growth in spring 

 as to spread a broad stream of silvery foliage and snow- 

 white bloom down seven or eight feet of rockery. The 

 two species offered by seedsmen are Biebersteinii and 

 tomentosum. There is little, if anything, to choose 

 between them, but a slight preference may be given to 

 the former. Alpinum and tenui folium are offered in 

 some of the plant catalogues. Neither need be chosen 

 before Biebersteinii, and this is hardly a genus of which 

 flower-lovers would care to make a collection. 



