REPRODUCTION OF PLANTS. 531 



of it under the influence of the parent plant and its specific formative 

 tendency. Of this we have two phases in the Rhizocarpece and Pha- 

 nerogamia : in the first, the influence exerted upon the development of 

 the pollen is mediate, as the seed-bud (ovule) is separated from the 

 parent plant ; in the Phanerogamia, on the other hand, it remains in 

 living union, whereby the developing new plant continues longer and 

 more entirely independent of the specific formative tendency of the 

 parent plant. Thus we see how the specific formative tendency encloses 

 the organism within constantly narrower limits of law, and also how 

 the circumstances of the parent plant under which the reproductive cell 

 must develope become more complicated, and thus communicate to it a 

 similar morphological development, and make it, as a new individual, 

 to represent the same formative tendencies as the parent plant. 



In the paragraph I have arranged the various modes of increase 

 of plants, according to the most general point of view, under four heads. 

 These may be subordinated again as follows : 



A. Immediately that every part of a plant is formed according to one 

 and the same principle of development, every part of the entire plant is 

 capable, through simple division of the plant, of producing a new inde- 

 pendent individual. This is increase of plants by division. 



B. But if in the plant the law of development exhibits an essentially 

 different kind of phenomenon, so that a part of a plant is not developed 

 into the entire plant, but receives the impression of the entire law of 

 development, then is the growth of the whole plant from a part impossible. 

 This occurs in the simple plants among the Gymnosporce, in which the 

 axis and the leaf, as two different processes of development, belong to the 

 idea of the whole plant. In this case the plants increase in the same way 

 as an elementary part ; a single cell would increase through the special 

 properties that were communicated to it. This same process, together 

 with accidental division, is normally present in the Angiosporce ; and this 

 process, in opposition to that of division, is called reproduction, and 

 is found present in all plants. But this reproduction presents itself under 

 two phases, as we have before observed : 



a. In the development of any living cell to a new individual under very 

 various circumstances = irregular reproduction, 



b. In the development of a special reproductive cell, exclusively 

 developed for this purpose = regular reproduction. This divides itself 

 into two, according to the circumstances under which the reproductive 

 cell is developed : 



1. The origin of the reproductive cell, independently of the parent 

 plant = asexual reproduction, as in the Cryptogamia. 



2. The development of the reproductive cell to a new individual under 

 the circumstance of a material influence of the parent plant. This last 

 we call sexual reproduction ; it is present in Rhizocarpece and Phanero- 

 gamia. This, and only this, is the signification of the word sex amongst 

 plants, and all comparisons with the higher animals are lame and unscien- 

 tific. We need an expression for these conditions in the vegetable king- 

 dom, and I would, with Valentin, banish the word sex, if it were not to 

 be feared that those who are not free from ignorant prejudices would, with 

 the abandonment of the word in the one kingdom, seek to do the same in 

 the other. If we divide the word sex into two, male and female, we must, 

 according to analogy with the animals to which the words are applied, call 

 those organs female in which lie the material organised (cellular) foundation 

 which subsequently becomes the new individual. If, then, we apply the 



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