48 THE HUMAN SIDE OF PLANTS 
pany of bachelor’s-buttons; and dandelions fre- 
quently grow among turnips and radishes. These 
clever habits allow many a plant that otherwise 
would be destroyed as a useless weed to have a 
permanent home and to bear fruit. 
Another example of the cleverness of plants in 
protecting themselves is the growth of all kinds of 
nuts on the trees. During the time of development 
they are green, the colour of the foliage, and there- 
fore hardly discernible; when, however, they are 
ready to fall to the earth in order to start new 
trees, they change to dark brown, the colour of the 
ground on which they are soon to rest. The hazel- 
nut is especially clever in its disguise, the nut being 
enclosed in a leaf-like green bract, which by its 
resemblance to the other leaves very effectually 
hides the nut from view. The walnut has a hard 
spongy covering filled with an acrid juice which is 
exceedingly distasteful even after the fruit has 
dropped to the ground. 
In waging war among themselves not always the 
stronger plant is victorious; ofttimes, apparently, 
the weaker uses ingenious methods and wins in the 
struggle for existence. Especially is this true of 
weak vines with delicate stems; the common morn- 
ing-glory, for example, climbs right over its more 
gifted neighbours, reaching its ambitious flowers 
