CHOICE PLANTS FOR ROCK GARDENS 189 
WAHLENBERGIA.—The genus Wahlenbergia contains a 
number of dainty little plants that are very closely allied 
to the Campanulas. They are not at all difficult to grow, 
but never look better than when wedged between closely 
packed stones, with a _ good 
body of soil behind them, into 
which their rambling roots may 
penetrate for moisture. W. ser- 
phyllifolium is the best species, 
of which there are a few varie- 
ties possessed of distinctive 
merits, such as enlarged flowers 
or richer colouring. The type 
itself has very attractive violet 
blue flowers, borne on slender 
wiry stems: (ne foliaze is nar- | WAStENBERGIA CENTIA- 
row, hence the name serphylli- see 
folia—foliage like Thymus serphyllum. W. gentianoides, 
here figured, is a daintily beautiful plant of slender growth 
but wonderfully free flowering propensities. 
ZAUSCHNERIA.—A_ well-developed bush of Zauschneria 
californica is one of the most striking plants one can 
have upon a rockery. Its colour is a most intense coral 
scarlet, the blossoms being long, tubular, and poised 
horizontally on stiff woody stems, in loose elegant 
spikes. The foliage is soft, downy, and of a greyish green. 
An established plant may grow to a height of 18 inches, 
and spread to 2 or 3 feet in diameter. An added merit 
is that the Zauschneria flower through the autumn, when 
brilliant colour on the rockery is particularly valuable. 

