PASTURE PLANTS 55 
Under certain conditions white clover and some other 
plants are useful members of permanent sod. 
There are many other plants in the pasture, which wecon- 
sider undesirable there, and hence call weeds. They mostly 
produce abundant seed and have excellent means of giving it 
wide dispersal. Many seeds find openings among the grasses. 
Fic. 31. Blue-grass (a) and timothy (b): flowering spikes and roots; 
with the two modes of producing new shoots underground shown 
at (c). 
A few of these plants survive by virtue of the same qualities 
that save the grasses. Some like the thistles and the teasel 
are spiny, and able to ward off destroyers. Many, like the 
mullein, the buttercup, the daisy and the yarrow, are un- 
palatable and are not sought by the cattle. Many grow well 
underground with only their leaves exposed to danger of 
trampling. If someleaves are cut off, new ones will promptly 
grow. Then, after a long season of growth, they suddenly 
shoot up flower stalks into the air, and quickly mature truit. 
They do this, too, at the season of abundant grasses, when 
their exposed shoots are least endangered by close cropping. 
Some, like the dandelions and the plantains, produce so many 
flower stalksthat they can survive the loss of some of them. 
Finally there are some, like the speedwells and the chick- 
weeds, so small that they are inconsequential. They merely 
fillthe chinks between the others. 
