HOW FLOWERS PLANT THEIR SEEDS.
Most people are familiar with the various novel methods that are
employed by plants in the distribution of their seeds. Many seeds are
winged so that they are carried by the wind, others are contained in
edible fruits to attract bids and animals - the seeds passing through
the digestive tracts uninjured and thus are transported considerable
distances to germinate and grow in a new locality. Still others are
supplied with barbes that become attached to the bodies of animals that
may be passing, and others equally interesting have other means of
"locomotion".
That various ingenious mechanisms are also employed in the release of
the seeds is not so well known. Apparently wild flowers seeds grow best
if planted in the autumn. Many of them however are forced, for want of
sufficient moisture in the fall, to flower in the spring. In such cases
the seeds, although they may be formed early in the year are usually
carried over the dry summer season by the parent plant.
A good example is the western anemone (Pulsatilla occidentalis). The
flower comes very early in the season, often pushing its way through the
edge of the receding snowdrifts and remain in bloom only a few days.
The fluffy silver gray seed-heads are carried all through the summer
however, the winged seeds not becoming sufficiently loosened on the
stalk to be carried away by the wind until late season.
The avalanche lily (Erythronium montanum), employ another clever
method. The seeds are formed in triangular pods that are carried erect
at the top of a slender stalk. When the weather becomes dry these open
but the seeds remain loose in the capsul and do not fall until the rains
begin again in the late summer. With the rains conditions are ripe for
planting and the seeds are mature and ready so the dry stiff stalk
absorbs moisture and becomes soft. Immediately the heavier seed pods
bends the stem and turns over, spilling the loose seeds on the moist
soil.
The pods of several other plants remain closed until conditions are
propitious and then, responding to the changed climate open suddenly and
with sufficient force to broadcast the seeds to the four winds. Still
others like the knobcone pine grow best after a fire. The cones will
not open until heated by fire to a point well beyond that possible by
the sun. So long as there is no forest fire the knobcone pine cones are
wasted, they never open.