530 ORGANOLOGY. 



ality of the whole plant, is able to produce a new plant. The isolated 

 cell must first stand in relation with the parent plant, and come under 

 the dominion of its specific formative tendency up to a certain point, 

 before it can be placed in circumstances to introduce the same law of 

 formative tendency into a new independent life. It is formed into a 

 little cellular corpuscle which is separated from the parent plant, as in 

 Mnium androgynum, Marchantia po/ymorpha, &c. From this point 

 and upwards ceases in the vegetable world the process of reproduction 

 through the separation of cells, and in its place commences the forma- 

 tion of buds. And here we arrive at an entirely unoccupied void in our 

 researches, which is filled up with mere hypothesis. Analogy allows 

 us the following conjectures : A parenchymatous cell, through the 

 growth of new cells, without becoming isolated upon the surface of the 

 plant, becomes the occasion of the origin of a mass of cellular tissue, 

 which is in close union with the plant, and scarcely to be distinguished 

 from the surrounding parenchyma, but at the same time it already re- 

 presents a special individuality, but as it originates entirely under the 

 influence of the specific formative tendency of the whole plant, it sub- 

 sequently becomes essentially independent of the parent plant, forms 

 the foundation of a plant with axis and leaf in a word, becomes a bud. 

 To what parts of the plant the first cell belonged is indifferent; and ac- 

 cording to all possible varieties are the circumstances various which 

 determine the development of the cell to the plant. In the axis of the 

 leaves these circumstances are always normally present, at the basis of 

 the leaves frequently, on the surface of the leaves and the ligneous axis 

 seldom, less frequent still on the herbaceous (annual) axis, and least 

 frequent of all on the parts of the flower. At the present we have no 

 accurate researches upon the formative processes which precede the 

 elevation of the bud upon the surface of the plant, and it would be only 

 through an accurate knowledge of the same that we should be in a 

 position to determine whether the facts are as I have above conjecturally 

 stated or otherwise. 



We must now follow another series, the development of the definite 

 reproductive cells (spores and pollen-grains) which are normally formed 

 for the development of the new plant. In the simplest Algce, as before 

 remarked, this process is scarcely to be distinguished. In the simplest 

 way a plant cell forms a filial cell (Brut-zelle), which after the destruc- 

 tion of its parent cell becomes isolated, and is developed into a new 

 plant. In the remaining Angiosporce, the process of growth in the re- 

 productive is connected with a peculiar law, which exerts a special 

 influence upon its nature. In the Lichens are first seen definite indi- 

 cations of a peculiar layer of separation which surrounds the repro- 

 ductive cells, and it is not improbable that it may preserve them from 

 those external agents which, upon the form of the process of develop- 

 ment, could exert any influence. In this also a new circumstance is seen, 

 which is afterwards found in all classes with the exception of plants 

 flowering under water. In the Rhizocarpece, however, the reproduc- 

 tive cell (spore), without further development, proceeds from the mass 

 of the plant and forms a new individual ; but from the Mosses upwards 

 we find that the origin of the same is connected with a definite morpholo- 

 gical law, and constantly originates in a determinate independence of the 

 specific formative tendency, and is exclusively connected with the form- 

 ation of the leaf. But in the Rhizocarpece a new stage sets in, not 

 only the formation of the reproductive cell, but the first development 



