2 THE HUMAN SIDE OF PLANTS 
tering of plants; especially is this true in moun- 
tainous countries, and near the sea, where the val- 
leys and cliffs are swept by the wind, and the tiny 
seeds are often carried together with dust and sand 
for great distances. The wind plants the sides and 
crevices of the most lofty mountains, some plant 
seeds being driven even across the Mediterranean 
Sea or the Atlantic Ocean, since they are frequently 
lighter than sand. The extreme minuteness of some 
seeds is almost incomprehensible to the human 
imagination. For example, a single capsule of a 
South African orchid has been found to contain 
the tremendous number of one and three-quarter 
millions of tiny seeds! 
We know that the ashes of volcanoes have been 
driven by the wind more than a thousand miles; in 
1845 an eruption took place in Hecla, Iceland, and 
some of the ashes were blown to Ireland and Eng- 
land. It is not strange, then, that often after a 
terrible wind-storm mountain-sides and high cliffs 
are covered with new flowers in nature’s own way of 
planting. 
But there are some plants which travel by actu- 
ally walking! 
Currant bushes, wishing to multiply, do not wait 
for such a slow process as dropping their seeds to 
the ground and letting them, little by little, sprout 
