Hardy Exotic Flowering Plants 153 



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bines are a northern and alpine family, most abundant in 

 Siberia. 



Wall Cress, Arabts. — Dwarf mountain plants, often 

 producing myriads of white flowers, suitable for sandy or 

 rocky ground, where the vegetation is very dwarf. With 

 them may be asso- 

 ciated Cardamine 

 trifolia and Thlaspi 

 latifolium, which 

 resemble Arabis in 

 habit and flowers. 

 All these are suited 

 for association with 

 the purple Aubrie- 

 tia or yellow Alys- 

 sum, and in bare 

 and rocky for gra- 

 velly places, and old 

 walls. 



Sandwort, Are- 

 naria. — Of these 

 little plants there 

 are certain kinds 

 that are vigorous 

 and useful, such as 

 A. montana and A. 



graminifolia. The small alpine species are charming for 

 rocky places, and as for the little creeping A. balearica, moist 

 rocks or stones suffice for its support. It covers such 

 surfaces with a close carpet of green, dotted with numerous 

 star-like flowers. Some of the smaller species, such as 

 Arenaria caespitosa, better known as Spergula pilifera, might 



3IBEaiAN COLUMBINE in rocky place. 



