Hardy Exotic Flowering Plants 191 



purpose they may be thrown into five sections — the mossy 

 section, represented in Britain by S. hypnoides ; the silvery 

 section, represented by S. Aizoon; the London Pride 

 section, by the Kerry saxifrages; the Megasea section, by 

 the large S. crassifolia; and the oppositifolia section, dis- 

 tinguished by its rosy-purple flowers. With the exception 

 of the Megasea and oppositifolia sections, which have rosy 

 flowers, most of the saxifrages have white blossoms spotted 

 with red ; a few are yellow, and all are very hardy, and the 

 easiest to grow of all alpine flowers. The mossy, silvery, 

 and purple saxifrages may be naturalized with the greatest 

 ease on bare rocky or mountainous grounds, amidst dwarf 

 vegetation ; but, as the places in which this kind of ground 

 occurs are comparatively few, the Megaseas and the Kerry 

 saxifrages are probably the most generally useful, as they 

 can fight their way amongst grass and other common herbs. 

 There are probably nearly 150 species in cultivation in 

 England. 



Houseleek, Sempervivum. — Very dwarf and succulent 

 plants, with their fleshy leaves arranged in dense rosettes, 

 and mostly with curious but seldom conspicuous flowers. 

 They abound in mountainous regions, and are very hardy. 

 The greater number of these grow quite as freely as the 

 common Houseleek in any arid soil, and in any position 

 where the vegetation is not taller than themselves, such as 

 on bare sandy banks, gravelly heaps, &c. There are about 

 fifty hardy kinds in cultivation in this country. 



Meadow Rue, Thalictrum. — Tall herbaceous plants, often 

 affording a pleasing effect when seen in groups, and hence 

 pretty for this mode of gardening. They grow in any soil, 

 and should be placed among rank vegetation. There are 

 many kinds not differing much in aspect; some of the 



