HARDY EXOTIC FLOWERING PLANTS. 131 
herbs, varying from a few inches to 4 ft. in height, and abundantly 
scattered in northern and temperate countries. Many kinds are in 
cultivation. All the medium-sized and large kinds thrive very well in 
rough places, woods, copses, or shrubberies, among grasses and other 
herbaceous plants ; while those smaller in size than our own harebell 
(C. rotundifolia) are quite at home, and very pretty, on any arid or 
bare surfaces, such as sandy banks, chalk pits, and even high up on 
old walls, ruins, etc. In such positions the seeds have only to be 
scattered. C, rapunculoides and C, lamiifolia do finely in shrubberies 
or copses, as, indeed, do all the tall-growing kinds. Where there are 
white varieties they should be secured ; many people will begin to see 
the great beauty of this family for the first time when they see them 
growing among the grass or herbs. The effect is far more beautiful 
than can be obtained in the garden proper. 
Red Valerian, Centranthus ruber.—This showy and pleasing 
plant is only seen in highest perfection on elevated banks, rubbish- 
heaps, or old walls, in which positions it endures much longer than on 
the level ground, and becomes a long-lived perennial with a shrubby 
base. On the long bridge across the Nore at Col. Tighe’s place, Wood- 
stock, Kilkenny, it grows in abundance, forming a long line on the 
wall above the arches; of course it could be easily grown on ruins, 
while it is invaluable for banks of all kinds, chalk pits, etc. and 
also for the level ground, except in heavy cold soils. Some of the 
larger Valerianas would grow freely in rough places, but none of them 
are so distinct as the preceding. 
Knap-weed, Centawrea.—Vigorous perennial or annual herbaceous 
plants, seldom so pretty as autumn-sown plants of our corn bluebottle 
(C. Cyanus). They are scarcely important enough for borders ; hence 
the wild wood is the place for them. Among the most suitable kinds 
may be mentioned macrocephala, montana, babylonica, and uniflora, 
the last more suitable for banks, etc. 
Mouse-ear, Cerastiwm—Dwarf spreading perennials, bearing a 
profusion of white flowers. Half a dozen or more of the kinds have 
silvery leaves, which, with their flowers, give them an attractive 
character. Most of these are used as bedding plants, but, as they will 
grow in any position where they are not choked by coarser plants, 
they may be employed with good effect in the wild garden. 
Wallflower, Cheiranthus.—The varieties of the common wall- 
flower afford quite a store of beauty in themselves for the embellish- 
ment of rocky places, old walls, etc, Probably other species of 
