Many of the trees also send their seeds on air voyages, in the hope of finding some piece of land that will give them a chance to grow into new, strong trees.
The seeds of the willow (Fig. [62]) have silky white sails such as we have found already in the plants of the milkweed and willow herb; and the cottonwood tree is so called because its tufted seeds remind one of the famous cotton seeds from which we get our cotton thread (Fig. [63]).
Fig. 62
There are other trees which use wings instead of sails when they send their seeds flying through the air.
Fig. 63
Here you have the winged fruits of the maple (Fig. [64]). In summer you see these winged fruits hanging in clusters from the trees; and later in the year they are thickly scattered along the village street and in the city squares.
Fig. 64