574 The Sex and Generative Organs of Plants. 



or they lie, as in the case of the Cambium or formation 

 sap, outside cells that are already formed, environed by 

 mucus and water. Just as we can trace the mode of 

 the organic increase in the cells transformed to wood, so 

 also can we the form and changes of the pollen granules 

 which in their development and sexual functions appear as 

 free and independent cells. But the embryos of sexless 

 plants also develope themselves in a similar way within a 

 larger or parent cell. 



Whatever, however, may be the mode in which the pollen 

 tube acts on the cell about to be impregnated (ovule) ; whe- 

 ther (according to Schleiden) it sinks down with its lower 

 end into the cavity of this cell, or there is only at ransfusion 

 of the pollen into the latter, the life of the elements of the 

 new plants always begins according to the universal forms of 

 growth. There is therefore a point of view, from which we 

 can plainly see, that the formation of the new individual is 

 subject to the laws of growth of the vegetable kingdom. 

 This view receives much confirmation from the process of the 

 formation of the embryos or sporules in several cryptogamia, 

 such as fungi and confervse. The latter plants consist of long 

 cylindrical tubes, which rest on each other like joints. They 

 form new embryos, by bringing into union with each other two 

 neighbouring tubes or threads at points opposite to each 

 other, by means of an intermediate organ, like the step of a 

 ladder, and bring together in this uniting organ their granular 

 contents, and roll them up into a large granule (the gongylus) 

 which at last, when extricated from its tough coverings, is 

 capable of sprouting out in the water, as a new individual. 



The comparison of the sexual process in vegetables with 

 the original formation and development of an animal ovum 

 shews us in a surprising way, that in the latter also the 

 process of development, is quite the same. For the animal 

 ovum is also originally a little bladder, provided with 

 a so-called cellular kernel (cytoblast) whose growth begins 



