82 ALPINE PLANTS 
banks, in exposed positions, where many plants would 
not exist. The variety Biebersteinii is the best and most 
effective. 
CHEIRANTHUS.—This is the botanical name of the Wall- 
flower family, but the genus includes several perennial 
and small growing species, varieties and hybrids that 
are more suitably dealt with as Alpine or rock plants than 
is the familiar wallflower of cottage gardens. The yellow- 
flowered Cheiranthus alpinus and the orange C. Allionii, 
or C. Marshallii, another orange-coloured variety of hybrid 
origin, and also C. mutabilis, an interesting plant that 
changes the colour of its flowers, sometimes showing pale 
cream, sometimes dark yellow, and then perhaps bronze 
or purple, may all be given exposed, sunny positions on 
the rockery, or, if planted in a bed, should have plenty 
of lime rubble, burnt earth and small stones about their 
roots. C. kewensis, C. linefolia, and a few other sorts 
of more or less mixed blood or hybrid character, are quite 
pretty and useful, and any of them may be propagated 
with ease by simply stripping off side growths with a heel, 
and inserting in sandy compost, August and September 
being suitable months for propagating. Established plants 
are greatly benefited by mulching in autumn with a mixture 
of road grit, mortar siftings, leaf soil, and a little fibrous 
loam. A very good plan is to plant in close company 
with each other plants of the kinds above named, allowing 
them to seed, and scattering the seeds, as soon as ripe, 
among the stones of the rockery or in the chinks of a 
roughly constructed stone wall, the latter position making 
an ideal home for all the Cheiranthus and their near 
