TREES WITH WINGED SEEDS Why do the trees grow in such mixed groves, when Nature does the planting? Here and there we find solid groves of beech or oak, but the forest is, for the most part, a gathering together of all kinds of trees. A part of the beauty of any woodland is this variety in the planting. Under a tall oak we find a hornbeam, and under this the witch hazel, and under the witch hazel, a carpet of low woodland plants. We may walk in a straight line, or follow a woodland path a mile, and find every tree we meet is different from all the rest.
Many reasons explain the order in which Na ture plants forests. One of the best of these is found in the kind of seeds trees bear. We shall find that trees most widely scattered are those whose seeds are winged. It is not hard to find, from May until far past midwinter, trees bearing light, winged seeds. All through the summer, the wind is busy sowing the seeds of the early-fruiting trees. In autumn, and all through the winter, the sowing of the larger crop goes on.
Let us begin our study with the maples, whose winged seeds every child knows. From the silver maple, whose seeds are dry before the first of June, there is a procession of ripening maple seeds that lasts throughout the year. A high wind shakes off the silver maple's keys in showers in late May. Watch those in the tree tops. The wind has a better chance up there. Each key, loosening from its twig, turns round and round in a dizzy whirl, and sails away still whirling as it falls, the heavy seed end always pointed downward. A tree is soon stripped, and the ground littered under it. But a great deal larger area than the tree's shadow has the seeds scattered over it : the stronger the wind, the further these seeds go. Before the summer is over, a crop of little maple trees springs up from this sowing.
The red maple's scarlet seed clusters turn brown, and the little winged seeds take flight in June. Lighter and smaller, they are carried longer distances than the seeds of the silver maple, and a crop of little red maples follows this June sowing of the trees.
I remember walking in a corn field in late June; the corn had been last ploughed a month before. Among the weeds that had grown up
in this short time was a crop of young red maples, now six inches high. It was amazing to see these little trees grow so plentifully in a culti vated field. I looked for the seed tree, and there it stood on the edge of the field, the only maple tree in sight. A few young trees were growing in the matted grass of the roadside un der the tree, but the great crop was from the seeds that flew out to the mellow ground between the corn rows. The disappointed seeds, those which fell and did not grow, were under the tree and in the dusty road.
In the autumn the hard maple, which we call the sugar maple, ripens its winged seeds. So does the three-leaved box elder (which is a maple) and the Norway maple, now a very fa miliar street tree. The wind takes its time, and the trees stubbornly hang on to their seeds, so that these maples are busy all winter with the sowing. Every day they give up a few, and many seeds that fall on the snow are picked up, again and again, by the wind and thus carried further and further away.
The maple seed, with its curiously one-sided wing, is the sign by which the maple family is easily recognised. Other trees have winged seeds, but none have the peculiar form of this one.
All summer long we may know the trees that belong to the ash family by the clusters of pale green darts that hang among their leaves. These are the ash seeds. Each one is a pointed seed case, containing the embryo plant, and out be hind it extends the thin, light, two-edged wing. There is no one-sidedness to this blade. The seed is winged, but balanced like a dart. When the wind loosens one from the wiry stem, it goes like an arrow, seed downward. If there is a gale blowing, the seed may be caught up and borne far away in the upper air, before a lull lets it take a downward course, and drive its point into a snowbank, or into the ground. This little feathered arrow may be long or short, de pending upon whether it belongs to the red ash, the white ash, or the black; but there is no mis taking an ash tree for any other, once the form of an ash seed is fixed in the mind.