In the eelgrass it is the specific gravity of the male flower, or, the secreted air bubble, which makes the flower lighter than the water, and actually causes the flight from the depths to the surface. Because of this, fertilization can only take place on the surface, although the flowers and fruits otherwise mature under water. But in sea wrack, in Naias, and in ditch grass, all submerged aquatics, the flowers are even fertilized under the water. Pollen in such plants is much modified, and instead of being in the ordinary form of pollen grains, it is, at the time of ripening, lengthened out into tubular, hairlike structures. These delicate prolongations of the male fertilizing stuff are carried by the currents of the water, just as a thread would be, but with the difference that the pollen threads are so beautifully weighted to fit their watery environment that they float, suspended, in the depths of the water at or near the level of the female flowers. The pollen is set free at maturity, just as it is in the eelgrass, but to meet the female, which never rises, it must float with the current of the stream. There must, as in the wind-carried pollen, be a tremendous wastage, yet sufficient quantities of it do fertilize the females, particularly in the ditch grass, which fruits very freely. Whether it be any of the various contrivances for insect fertilization, or by the winds, or, as in the eelgrass, by the water, the climax of the flower’s life is always reached in this act. For all annuals the plants, also, begin to die down then, a process that is completed with the production of seed, which is, of course, the object of all those varied modes of fertilization. Perhaps no answer to the question of why plants do not always self-fertilize themselves is so eloquent as the hundreds of ways they have adopted to avoid doing so, a few of which we already know. Many volumes have been written on this subject, but all of them, intricate as the methods they describe nearly always are, merely confirm what we have already seen--that rather than submit to self-fertilization, plants will adopt almost undreamed-of expedients. Sometimes, as in the eelgrass and in the visits of nocturnal insects to those night-blooming flowers that carry on their matings in the glamour of moonlight or in the dusk of eventide, the drama, in the eyes of imaginative writers, is one of singular beauty and charm. And, on the other hand, we have seen the well-nigh heartless cruelty of the Dutchman’s-pipe in keeping as prisoners its absolutely necessary insect deliverers. Even this is outranked for matchless ruthlessness by a wild arum, a relative of our jack-in-the-pulpit, from the East Indies. It produces a club-shaped inflorescence composed of tiny flowers that need cross-fertilization, but so offensive is the odor of the flower that no insects will tolerate it. A snail, a voracious eater of foliage, is attracted to the flower partly by the fine fleshy leaves, but mostly by