310 DR. M. J. SCHLEIDEN ON PHYTOGENESIS. - 



like development, the distinction depends in fact on the larger 

 or smaller number of cells that are converted into porous ves- 

 sels. 



There are, however, a vast number of gaps still to fill up : and, 

 more especially, the origin of the medullary rays and their rela- 

 tion to the wood, the formation of the new bark, and lastly, the 

 origin of the buds in the wood, are so many questions for ex- 

 tensive researches, to the execution of which, however, we may 

 look forward at no distant time, considering the ardent and gra- 

 tifying zeal which has been awakened and cherished, especially 

 among our contemporaries, in behalf of the sound and scientific 

 study of the anatomy and physiology of plants. 



I have, as far as lay in my power, attempted in this Memoir 

 to solve many interesting questions in vegetaljle physiology ; or, 

 by more accurate definitions of the question, to advance nearer 

 to a future solution. May these observations meet w ith a friendly 

 reception, and be speedily improved upon and extended among 

 the vegetable physiologists of Germany. 



EXPLANATION OF PLATES XV. AND XVI. 



Fig. 1. Cellular tissue of the albumen from the embryo-sac of 

 Chamcedorea Schiedeana in the act of fomiation. a. The inner 

 mass consisting of gum with intermixed mucous granules and 

 cytoblasts. b. New cells, still soluble in distilled water, c — e. 

 Further development of the cells, which by a slight pressure still 

 form into an amorphous gelatinous mass, with the exception of 

 the cytoblasts. 



Fig. 2. The formative substance from fig. 1. a. more highly 

 magnified, gum, mucous granules, nuclei of the cytoblasts and 

 cytoblasts. 



Fig. 3. A single, still free cytoblast, still more highly magnified. 



Fig. 4. A cytoblast with the cell forming on it. 



Fig. 5. The same, more highly magnified. 



Fig. 6. The same. The cytoblast here exhibits two nuclei 

 and is represented in Fig. 7. in an isolated state after the destruc- 

 tion of the cell by pressure. 



Fig. 8. The same cellular tissue still further advanced in de- 

 velopment than in Fig. 1. e. The walls of the cells in contact 

 already cohere. In a. their horizontal section, it may be distinctly 

 perceived that the cytoblast is inclosed in the cellular wall. 



Fig. 9. Cells of the nearly mature albumen in a thin cross 

 section. 



Fig. 10. Common septum between two cells fi*om Fig. 9. under 



