Forest and stream . POND SCUM. condition until the next spring. Then, under the influ-ence of warmth and light they grow into new plants. Inthe Spirogyra a zygospore is formed by the union of twocells of contiguous filaments, this union being considereda sexual process. Quite common in midsummer is the very curious littleplant called the volvox. To the naked eye they appearlike little green balls slowly rolling through the really consist of a mass or colony of cells in the. form of a hollow sphere. Each cell is provided with apair of vibrating cilia which project into the water, giv
Forest and stream . POND SCUM. condition until the next spring. Then, under the influ-ence of warmth and light they grow into new plants. Inthe Spirogyra a zygospore is formed by the union of twocells of contiguous filaments, this union being considereda sexual process. Quite common in midsummer is the very curious littleplant called the volvox. To the naked eye they appearlike little green balls slowly rolling through the really consist of a mass or colony of cells in the. form of a hollow sphere. Each cell is provided with apair of vibrating cilia which project into the water, giv-ing the ball a hairy appearance, and by their movementspropelling it through the water. In the hollow of thesphere other smaller balls may be seen, and examinationshows that they are precisely the same as the larger one,forming an instance of life within life. After a time thesesmaller ones escape and begin a career of their own. Afriend of the writer says that he saw many of these plantsin one of the Adirondack lakes a few years ago at aboutmidsummer. They were so thick that water could not bedipped up without catching many of them. Another curious plant common in ponds is Hydrodict-yon, or the water net. It consists of a tubular net com-posed of very many elongated cells attached at their the net is 10 or 12in. long, and the cells one-third of an inch long. In this plant, too, a miniatureplant (in this case a net) is formed inside the parent andfinally escape
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectf, booksubjecthunting
