The Origin of a Land Flora
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| Hersteller: | Forgotten Books (Bower, F. O.) |
| Stand: | 2015-08-04 03:50:33 |
Produktbeschreibung
Excerpt from The Origin of a Land Flora: A Theory In the year 1874 apogamy was discovered in Ferns by Farlow: and in 1884 instances of apospory in Ferns were demonstrated before the Linnaean Society of Iyondon by Druery. These events stimulated a fresh enquiry into the nature and origin of Alternation in Archegoniatc Plants. My own observations on apospory confirmed my interest in this question: it seemed to me probable that some biological cause had determined the prevalence and constancy of the alternation, to which apogamy and apospory appear as occasional exceptions. The theory was entertained that the change of conditions involved in the invasion of the land by organisms originally aquatic had played a prominent part in the establishment of those alternating phases of the life-cycle which are so characteristic of Archegoniatc Plants. As early as 1889 I had already written several chapters of a treatise on this subject: but the necessary facts were found to be then so imperfectly known that the work was abandoned, and instead of a full discussion of the matter, the Biological Theory of Antithetic Alternation was briefly stated in a paper published in the Annals of Botany in 1890 (vol iv. p. 347). The main position of Celakovsky in discriminating between Homologous and Antithetic Alternation was adopted; but the latter type, as seen in Archegoniate Plants, was recognised as having been fixed and perpetuated in accordance with the adaptation of aquatic organisms to a I-and-Habit The Studies in the Morphology of Spore-producing Members were then entered upon as preliminary investigations to elucidate the facts requisite for a more full statement, and they were published in five parts, from 1894 to 1903. Meanwhile, in 1894 Strasburger contributed to the Meeting of the British Association in Oxford his paper on the "Periodic Reduction of Chromosomes." He brought together a wealth of facts establishing the cytological distinction of the alternating generations, and his theoretical position was virtually identical with that of my paper of four years earlier. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
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