74 the ASSOCIA^TIONS OF FLOWERS 
these flowers is, however, much used by chemists, to 
detect the presence of acids and alkalies. 
Some of our most beautiful species of butterfly feed 
entirely upon the sweet violet. The stem of this plant 
often presents, during winter, a swelled and spongy ap- 
pearance. This is caused by insects, the eggs of which 
were desposited on the stalk during the preceding summer. 
The little animal, upon being hatched, finds its food 
ready for it; and, penetrating into the plant, disturbs its 
juices, and causes this excrescence. The punctures of 
several insects, chiefly of the genus Cynips, give this 
swelled appearance to several other plants. They cause 
the smmll red excrecences common on the leaves of many 
species of willow tree ; and a similar production at the 
end of its branches has given its name to the rose willow 
(Salix helix). The mossy ba]ls which grow upon rose 
trees, and the oak galls procured from the south of 
Europe, for the manufacture of ink, are formed by the 
same process. The galls of one kind of willow (Salix 
pomifera) are even agreeable to the taste, and are valued 
as a delicacy in eastern countries. 
We have too many cultured violets, to render a sepa- 
rate description of them desirable. They make a pretty 
addition to the garden in spring. It is the wild sweet 
violet, however, with its blue or white petals, which is 
the chief favourite of the tribe, on account of its con- 
nection with scenes and seasons dear to all. If we except 
the daisy, there is no flower of the wood or meadow 
which has been so long and so often celebrated. Among 
those early wandering bards, the Troubadours, it was 
considered the loveliest of all flowers ; and the far-famed 
prize of a golden violet, which was given at Toulouse, to 
him wTo produced the best poetical composition, not only 
showed the estimation in which these poets held it, but 
served to increase and continue the poetic admiration of 
the flower. The poem on the Golden Violet, which that 
lamented lady, Mrs. Maclean, wrote some years since, 
has made the subject of the floral prize familiar to most 
readers. The floral games of Toulouse were instituted 
by Clemence Isaure, a lady of the fourteenth century ; 
and she is represented as sending, during a weary im- 
prisonment, her chosen flower, the violet, to her knight, 
that he might wear it in honour of her. 
