258 THE ASSOCIATION'S OF FLOWERS 
pollen^ and is very conspicuous on the stamens of large 
flowers, as the white lily, where it often colours with 
yellow the faces of those who approach very near ta 
inhale the fragrance of the blossoms. When the minute 
flowers of the pellitory of the wall are first formed, the 
threads, or stamens, all bend inwards. As soon as the 
pollen is quite ripe and the sun shines upon it, the stamens 
fly back instantly, and a quantity of dust is discharged 
from them. The same effect is produced if they are 
touched ever so slightly with the point of a pin. 
Then, there is the little white-flowered whitlow grass 
(Draba verna), which grows in small tufts of a few inches 
high on many a stone or brick building, and almost es- 
capes observation, from its diminutive size ; and there are 
ferns and mosses which cannot be individually described, 
but which lend their grace to hide decay. Sometimes a 
stray flower, like the pale yellow toad-flax, or the brighter 
yellow hawk-weed, is sown on the wail by the birds of 
the air, and grows there for a season, though on an un- 
kindly soil. Occasionally even a tree, whose seed was 
borne thither by these winged planters, sends out its 
roots, and spreads abroad its branches, and shoots forth 
its green leaves to the sun and dew; 
“ And there it lives a huge tree flourishing. 
Where you would think a blade of grass would die.” 
But the plant which peculiarly inhabits the soil of the 
mouldering tower or building, the “ yellow wall - flower 
stained with iron brown,” as Thomson calls it, is as 
common throughout our island as any wild-flower, and 
everyone knows it too well to need a description of its 
appearance. The Cheiranthus cheiri, with its shrubby 
stem and yellow blossoms, is one of the sweetest- scented 
flowers of the early year. This is the same species as 
the common wall-flower of the garden ; but the additional 
nutriment gives its petals, when planted on the bed, a 
deeper stain of the iron-brown than they have when they 
grow unattended by human hands, sown by birds, and 
watered only by the spring rains. It was regarded by the 
Troubadours as the emblem of faithfulness in adversity, 
because it smiles upon the ruin. Its old name was that 
