PLANTS THAT BUILD AIRSHIPS 115 
flowers come like those of the parent plant—and the 
flowers develop into seeds. 
The linden provides a kite for its seeds, and hurls 
them through the air by means of this device, which 
is so constructed that the wind carries it spirally 
toward the earth, often landing it a great distance 
from the mother-tree. Should this kite with its 
passenger by accident fall into water, it is prepared 
to float for a long period of time, and if not too 
far from land it may drift back to shore, like a 
shipwrecked sailor. 
The bladdernut is still more ingenious. It builds 
an airship with three separate compartments; and in 
each compartment it places a tiny seed-aviator. 
Then it sends them forth, secure in the thought 
that if by chance the airship should fall into water, 
it will immediately turn into a boat, its bladder- 
like compartments keeping it from sinking, and 
all the aeronaut-seedlets will be saved. 
' The airship plants have learned to adopt all the 
best contrivances for the safety of their passengers. 
The wings on the flying seeds have been adapted 
to service as sails also. See the weary seed-aeronaut 
sink gently on the surface of the water. He lies 
there quiet a moment, the tiny feather-sail lightly 
swaying. A puff of fresh wind ripples the sur- 
face. The seed-sailor steadies, the sail fills and 
