In late March, or early in April, before the leaves have come out on any
of the trees along your street, you may look out of an upper window and
notice that strange-looking tassels are hanging on the twigs of a poplar
or cottonwood tree. Its buds are large and they shine in the sun, as if
they were wet. A day or two later you may be walking with your mother or
sister, and she will be startled to see the sidewalk covered with what
look to her like great red caterpillars! Then you may remember the tree
with the tassels on it, and recognise them, and explain where they came
from.
A single look shows that this worm-like object is a catkin, and the
lovely red is the colour of the many stamens that contain the pollen
dust. When this is ripe the stamens burst and let it fly away. Then the
tree lets its catkins fall, for they have done their part.
Green catkins hang on other trees of the same kind in the neighbourhood.
The flowers are waiting for pollen that will enable them to set seed. If
the wind blows in the right direction when the pollen is flying about,
the green, fertile flowers will get all they need. These catkins are not
shed as the red ones are. They make little show among the opening leaves,
but little seed balls take the place of the flowers. By the end of May
the green balls the size of peas turn yellow, and open. Out of each pod
floats tufts of white down, each bearing away a tiny white seed. This is
the end of the story. Before the chestnut trees have begun to blossom,
the poplars have scattered their seeds, and have all the summer to spend
in growing long, supple shoots covered with their dancing, shining
leaves. They look as if they enjoy life!
The pussy willows push their fuzzy noses out in winter. Some are even
showing in autumn. But the yellow pollen is not seen on these flowers
until the catkins are full grown, and they wait till winter is past. They
dare not risk a frost.
Among pussy willow trees there is a difference in the catkins. On one
tree they turn yellow when mature; the golden pollen dust rises in a
cloud when the twig is disturbed. These catkins soon fall off.
On other trees the catkins are greenish, and they stay on after reaching
full size. They are the fertile flowers, which develop into seed pods.
Pollen brought to them by the wind or by visiting insects in search of
nectar, insures the setting of seed in these flowers. Though the gayer
flowers fall, they are quite as necessary to the making of seeds as the
fertile ones. In all the willows and poplars, it requires two trees,
bearing the two kind of flowers, to make the seed. And the wind and
nectar-seeking insects are necessary as pollen-carriers.
[Illustration: The winter flower buds, the blossoms, the full-grown
winged seeds, and the ribbed leaf of our American elm]
[Illustration: The majestic, fan-shaped elm blossoms while snow is still
on the fields]
In marshy land, or by a brook or river, or even just outside the window
at home, there is a tree that turns rosy in March with a multitude of
small red flowers clustered on the sides of its twigs. It is the swamp
maple, the red maple, the river maple, the scarlet maple. Two of these
names tell of the tree’s thirst; two name its colour when in blossom, and
also when the leaves change colour in autumn.
Each flower is a red bell, for the petals are red. One has a red forked
pistil thrust out; another lacks a pistil, but has a cluster of yellow
stamens. One tree may be deep red throughout, having only pistillate
flowers. Another may have only staminate flowers; it will be orange
coloured, by the blending of the colours of the yellow stamens, and the
red petals. Another tree may have flowers of both kinds. Occasionally
flowers will be found that have both stamens and pistils.
The bees are in the scarlet maples at the first loosening of the bud
scales. There is nectar in those flower bells. The colour and a faint
fragrance tell this secret. From pollen flowers the busy insects carry
the golden dust to the forked pistils that set seeds.
The wind helps by scattering pollen in the tree tops, and very soon the
flowers are gone. The staminate trees turn green when the opening leaves
lose their vivid red. The pistillate trees hang out red clusters of
winged seeds below the opening leaf clusters. These red trees keep their
name written plainly as long as the seed clusters swing.
Early in March, the side buds on the elm twigs begin to swell, and soon
clusters of purplish flowers, small but very pretty, come out of the
largest buds, and the tree top has a purplish haze upon it, that means
that spring is coming. The bees come to get nectar from these early
blossoms, but few people speak of the blossoming elms. They do not notice
that elms ever blossom; and are rather incredulous when a spray is shown
them covered with the graceful little tassels. “Who ever _heard_ of elms
having flowers?”
The truth is that every tree, when it is large enough, bears flowers. Not
every one bears fruit, for some have pollen flowers only, the seeds being
borne on the fertile trees. Elms have perfect flowers, and soon after the
leaves open, the green fruits are seen in clusters, and before May
passes, the seeds, each surrounded by an oval wing, flutter off in the
wind.