REPRODUCTION OF PLANTS. 529 



8. All plants form, in a normal manner, in morphologically dis- 

 tinct organs, cells, which are to become new and independent 

 individuals. They are seen in the three forms of the process of 

 development in the Cryptogamia, JKhizocarpece, and Phanerogamia, 

 in which the reproductive cells are the spores and pollen granules. 



The eight preceding kinds of reproduction resolve themselves 

 into four classes: 1. Reproduction through corporeal division, and 

 only occurring in the Angiospora (1.); 2. That peculiar to the 

 Angiosporce and rootless Gymnosporce, that is, reproduction by 

 single parenchyma cells (3.); 3. That of Gymnosporce, proceed- 

 ing from the formation of buds alone (2. 4. 5. 6. 7. 134.); 

 4. That which occurs in all plants presenting the formation of 

 reproductive cells (8.). 



If we maintain what has been said upon the reproduction of individual 

 cells and the process of growth, it results therefrom that every mass of 

 cellular tissue, under whatever form it presents itself, as also the entire 

 plant, has its origin in an individual cell, through whose reproduction 

 through many generations the cellular tissue is produced, and we have 

 to determine for the various species in what relations the individual cells 

 stand to the whole plant, and what circumstances it requires in order to 

 develope a new individual. The less a plant exhibits morphologically 

 definite forms, the less circumscribed is the formative tendency which 

 holds the cells together in the entire plant ; in consequence, the cell-life 

 will be more independent, and the formative power will be more easily 

 communicated to individual cells, which, as the result of their multipli- 

 cation, are arranged in the loose outlines of the parent -plant. Whilst, on 

 the other hand, the more powerful the formative tendency is towards 

 the independence of the elementary organs, the more manifold and pe- 

 culiar are the forms in which the specific characters of a plant are dis- 

 played, and consequently more intense and permanent must the influence 

 be which the entire plant exerts upon individual cells and their develop- 

 ment into new plants : hence these remain perfectly under the dominion 

 of the same formative tendency, and are a true impression of its type. 

 Therefore, in the simplest plants, as the Protococcus viridis, which only 

 in their elementary organs can be regarded as a species, every formation 

 of a new cell is an act of reproduction, and the new cell requires, in 

 order for the species to remain true, nothing more than the unencum- 

 bered development of the universal cell life. In the constantly inde- 

 finite forms of the Angiosporce (in which, however, the individual life 

 of the cell is brought under an unvarying formative energy), reproduc- 

 tion is divided into two kinds, one from the mass of the cells, the other 

 from a single cell, each originating under a definite form of the processes 

 of formation, and serving exclusively and necessarily for reproduction. 

 We find a continuous series from the almost entire identity of both pro- 

 cesses (in the formation of a special cell) in the simplest Algce, even to 

 one of the customary reproduction of the cell through the peculiar 

 phenomena of essentially varied generation of the definite reproductive 

 cells in the Lichens. In the Mosses and Liverworts, the formative ten- 

 dency exhibits a more strict and limited conformity to law, as is seen in 

 the presence of an axis and leaves, and in the more complicated forms 

 of the remaining organs. Here ceases the first kind of reproduction, in 

 which a single cell, withdrawn from the mass constituting the individu- 

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