There's a dance of leaves in that aspen bower; There's a titter of winds in that beechen tree; There's a smile on the fruit, and a smile on the flower, And a laugh from the brook that runs to the sea. And look at the broad-faced sun, how he smiles On the dewy earth that smiles in his ray; On the leaping waters and gay young isles-- Ay, look, and he'll smile thy gloom away! William Cullen Bryant. [Illustration: LADY'S SLIPPER. (Cypripedium hirsutum.) COPYRIGHT 1900, BY A. W. MUMFORD, CHICAGO.] FLOWERS AND THEIR INVITED GUESTS. It must be taken for granted in this paper that the reader has such knowledge of the parts of the flower as could be obtained from the paper on "A Typical Flower," printed in the June number. When flowers first appeared it became necessary to secure the transfer of the pollen grains to the stigmas. This was necessary in order that the ovule might be developed into a seed containing a young plant or embryo. At first the currents of air were selected as the agents of this pollen transfer, and the flowers were adapted to what is known as wind-pollination. As the wind is an inanimate agent any transfer by it is largely a matter of chance. In order to increase the chances of successful pollination it was necessary for pollen to be developed in enormous quantities, so that it might fall like rain. In this way stigmas would be reached, but at the same time an enormous amount of pollen would be wasted. The evergreens are good illustrations of wind-pollinated plants, and their showers of pollen are very familiar to those who live near pine forests. When these showers come down in unaccustomed regions they are often spoken of as "showers of sulphur," and the local newspapers are full of accounts of the mysterious substance. In wind-pollinated plants not only must the pollen be excessively abundant, but it must also be very light and dry. Sometimes the buoyancy is increased by the development of wings on the pollen grains, as in the case of pines. This habit of pollination is found not only among the evergreens, but also among many important families of the higher plants, as in the ordinary forest trees, the grasses, etc.