92 The Romance of Wild Flowers 
useful to plants once dependent upon the visits of 
insects, but which have now learned to do without 
them. The presence of these 
minute white petals, and in some 
cases honey-glands that no longer 
secrete honey, testifies to the fact 
that these plants have come down 
in the world. Yet, in spite of 
_ their lack of show or “ presence,” 
they are a standing rebuke to 
those writers who have so 
strongly asserted that cross - 
fertilisation produces a more 
vigorous and successful race. 
What cross-fertilisation by insect 
agency does is to produce more 
brillant individuals, and to keep 
-up large flowers of bright hue. 
# ip fact, it produces a kind of 
floral aristocracy; whilst the 
principal work of the vegetable 
kingdom — the abstraction of 
| carbon from the atmosphere, the 
Shepherd’s Purse setting free of oxygen, the pro- 
duction of food for the entire 
anim done mainly by the less brilliant 
weeds and grasses and trees,—the working classes. 
Sir Joseph Hooker has recorded his opinion that, 
of the numerous weeds of this character that cling to 
the skirts of husbandry and seldom appear on virgin 
soil, the Shepherd’s Purse would be among the first to 
disappear entirely if the soil were unleft disturbed by 
man and the animals he rears. It has long been 
