. Plant life and plant uses; an elementary textbook, a foundation for the study of agriculture, domestic science or college botany. Botany. LIVERWORTS 401 spores out of the ripe sporogonium. The spores are light and may then be scattered by currents of air. Thus you see the advantage which it is to the plant to have its sporogonia borne on stalked organs whose stalks elongate after fertilization has occurred. This little history of the sex method of reproduction in a liver- wort, and of what happens after the egg is fertilized, illustrates what is called the alternation of generations, and thi
. Plant life and plant uses; an elementary textbook, a foundation for the study of agriculture, domestic science or college botany. Botany. LIVERWORTS 401 spores out of the ripe sporogonium. The spores are light and may then be scattered by currents of air. Thus you see the advantage which it is to the plant to have its sporogonia borne on stalked organs whose stalks elongate after fertilization has occurred. This little history of the sex method of reproduction in a liver- wort, and of what happens after the egg is fertilized, illustrates what is called the alternation of generations, and this is a matter important enough to have a head- ing of its B. Alternation of Generations. â In animals the fertilized egg produces a form like its parent. Fig- i From the egg of a chicken we get another chicken. There is no al- ternation of generations. The gen- erations are all alike. But in plants, at least from liverworts up, the fertilized egg does not produce a form like its parent. It produces a form like its grandparent. One generation is not succeeded by another just about like it; it is succeeded by one which is not like it at all. Then this new, entirely different generation produces in turn, not itself, but the generation which produced it. Let us see how this is illustrated in the liverwort. You â Section through the sporogonium of MarchanUa. This structure hangs down from beneath the top of the ripe archegoniophore. Note that it has three parts. The largest part is the capsule. It contains the spores. Scattered among the spores the spiral elaters are seen. Above the capsule there is the sialic or je<s, and above that there is the foot which is embedded in the tissue of the archegonio- 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 Coulter, John G. (John Gaylord), b. 1876. New
Size: 993px × 2518px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
