DESCRIPTIVE LIST OF THE BEST KINDS 219 



growth, and form compact cushions of bright green 

 foliage, studded with numerous flowers in spring. They 

 are excellent for dry walls, or may be grown in sunny 

 crevices, planted in very gritty soil. In cracks where 

 plants cannot be inserted seeds mixed with a little soil 

 should be sown, and the plants will soon establish them- 

 selves. There are numerous kinds in cultivation. D. 

 Aizoon is a native plant, found on old walls and rocks 

 in the west of England. It forms a dwarf spreading tuft, 

 which in spring is covered with bright yellow flowers ; 

 D. bruniaefolia, from the Caucasus, is a free growing 

 kind, forming a low turf of deep green foliage, and pro- 

 ducing large yellow flowers. D. Dedeana, from Northern 

 Spain, is one of the most distinct, with white flowers 

 crowded into a dense mass. It is an excellent subject 

 for the moraine, growing freely, and flowering profusely 

 under these conditicps of gritty soil and moisture. D. 

 imbricata, from the Caucasus, is an early-flowering 

 species with heads of yellow flowers on slender stems. It 

 is one of the prettiest and is a recent introduction. D. 

 pyrenaica, well known as Petrocallis, is another moraine 

 plant of great beauty, forming little tufts barely half an 

 inch high. In April and May the pleasing rosy-lilac 

 flowers are produced, forming quite a sheet of colour 

 over the plant. D. tomentosa is a woolly leaved kind, 

 much liable to damp off in winter. All the Drabas may 

 be grown in very gritty, well-drained soil. Seeds are 

 freely produced by most of the different kinds, and they 

 germinate quickly when sown in the spring. 



