. Introduction to botany. Botany. aio Introduction to Botany. the rich deposits which have accumulated at the mouths of rivers. Much of the variation resulting in the great multiplicity of form and structure which we now see has originated in the different environments found by plants by means of their migrant seeds. We see, then, that from many points of view it is im- portant to plants to produce reproductive bodies capable of dispersion by their own movements or by natural agents outside of them- selves, such as the wind, running water, birds, in- sects, etc.; and we may expect to find a gr
. Introduction to botany. Botany. aio Introduction to Botany. the rich deposits which have accumulated at the mouths of rivers. Much of the variation resulting in the great multiplicity of form and structure which we now see has originated in the different environments found by plants by means of their migrant seeds. We see, then, that from many points of view it is im- portant to plants to produce reproductive bodies capable of dispersion by their own movements or by natural agents outside of them- selves, such as the wind, running water, birds, in- sects, etc.; and we may expect to find a great vari- ety of devices intended to facilitate the scattering of fruits and seeds. 145. Dispersion by Elas- tic Tissues. — The seeds of the wild cranesbill are scattered by a sudden springing outward of the valves of the carpels. This action is caused by the outer layers of cells being more succulent and shrinking more on drying than the inner layers. The ripened seeds lie loosely in the inflated lower portion of the carpels, and are conse- quently thrown out when the carpels spring upward (see Fig. 125). When the fruits of the common Euphorbias are picked and placed on a table in a dry room, the carpels suddenly spring apart as they become dry, and hurl the seeds with considerable force to various parts of the room. Of course they act in the same way under natural conditions out of Fig. 125. Elastic carpels of Cranesbill; seed being thrown on tlie right. After Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Stevens, William Chase, 1861-. Boston, D. C. Heath & Co.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1902
