54 
SEED DISPERSAL. 
fishing, or coasting on the hillside. Try experiments with 
seeds of catalpa, trumpet-creeper, wild yam, pine, spruce, 
arbor vitas, and fruits of maple, box elder, birch, hop tree, 
blue beech, ailanthus, ash, tulip tree, — in fact, anything 
of this nature you can find, whether the name is familiar 
or not. No two of them will behave in all respects alike. 
34. Plants which preserve a portion of their seeds for an 
emergency. — Many a great general or business man has 
learned by experience and observation that it is usually 
unwise to exhaust all resources in one effort. If possible, 
he always plans to have something in reserve for an 
emergency — a loophole for escape from difficulty. We 
have seen in many instances that plants are endowed 
with the same trait. This is well illustrated by the way 
in which the jack-pine, Pinns [ Banksiana ] divaricata, 
holds in reserve a portion of its seeds, to be used in case 
the parent trees are killed by fire. In 1888 I made a 
study of this tree as it lives on the sandy plains of 
Michigan. The tree is often killed by fire, and never 
sprouts from the stump, as do oaks, willows, cherries, and 
most other trees. The jack-pine grows readily and rapidly 
from seed dropped on the sand, and begins to bear cones 
and seeds in abundance while it is yet only a few years 
old, perhaps as young as five years in some instances. 
The cones open slowly to liberate their seeds, some of 
them only after months or even years, and in some cases 
they never open at all. I have seen cones containing 
good seeds that had been nearly grown over by the tree. 
