. Lectures on the evolution of plants. Botany; Plants. MOSSES AND LIVERWORTS 103. among the algge is found in the stoneworts (Characese), but the differences in the vegetative parts between these and the Hepaticse are too great to admit of the idea of any but the remotest relationship existing a between the two, and at present it must be admitted that the gulf between Algse and Archegoniates is a very deep one. The antheridium is not so different from that of some algse, but is much more com- plicated than in any but the Characese. In the Archegoniates it has the form of a capsule (Fig. 26, C)
. Lectures on the evolution of plants. Botany; Plants. MOSSES AND LIVERWORTS 103. among the algge is found in the stoneworts (Characese), but the differences in the vegetative parts between these and the Hepaticse are too great to admit of the idea of any but the remotest relationship existing a between the two, and at present it must be admitted that the gulf between Algse and Archegoniates is a very deep one. The antheridium is not so different from that of some algse, but is much more com- plicated than in any but the Characese. In the Archegoniates it has the form of a capsule (Fig. 26, C), which in the lower forms is usually stalked. The central part is divided into many small cells, in each of which is developed a spermatozoid. The latter is very much like those of most alg?e, and like them is provided with cilia (Fig. 26, D). Throughout the whole group of the Archegoniates water is necessary for the opening of both archegonium and antheridium, the water swelling up the mucilagi- nous cell-walls of the interior of the organs, thus forcing them open. The liberated spermatozoids then swim to the open archegonium, which in the mean time has dis- 3>C. Fig. 26. — A, longitudinal section of the archegonium of a liverwort (Targionia), showing the central row of cells; B, a similar section of the ripe archegonium of Biccia; the cells of the axial row are disorganized and the egg, o, lies free in the enlarged venter of the archegonium ; C, longitudinal section of the antherid- ium of Biccia, showing the mass of sperm- cells surrounded hy a single layer of peripheral cells; D, a free spermatozoid of Fimbriaria 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 Campbell, Douglas Houghton, 1859-1953. New York, London, The Macmillan company
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Keywords: ., bookcentury1900, bookdecade, booksubjectbotany, booksubjectplants
