A PRELIMINARY REPORT ON THE STRUCTURAL 



ELEMENTS OF THE CYTOPLASM IN 



PLANT CELLS. 



ROBERT H. BOWEX, 



DEPARTMENT OF ZOOLOGY, COLUMBIA UNIVERSITY. 

 ONE PLATE. 



In several recent papers (Bowen, '260., b, c) I have reported 

 briefly on some aspects of cytoplasmic structure in plant cells, 

 as revealed in the first stages of an extensive study of the problem 

 as a whole. This investigation has now been pushed con- 

 siderably farther and much more complete results are in hand. 

 Errors in my earlier reports, both of omission and commission, 

 have now become evident, and I propose in this paper to restate 

 the major results by way of correcting and extending my previous 

 accounts, pending the completion of more extended papers, now 



in preparation. 



MATERIAL. 



My study thus far embraces material from each of the three 

 higher plant groups, Bryophyta, Pteridophyta and Spermato- 

 phyta, as follows: 



Bryophyta male heads (including developing sperm cells, anther- 

 idial epithelium, and cells of the paraphyses and leaves) of 

 Polytrichum juniperinwn, piliferum and commune. 



Pteridophyta growing-point and root-tip of Equisetum arvense. 



Spermatophyta young shoots of barley and root-tips of Vicia, 

 Pisum, Ricinus, Hyacinthus, barley, pumpkin and kidney 

 bean. 



Some of this material has received as yet only preliminary study 

 but so far as the results go, there appears to be a surprising 

 uniformity in plant cells of all kinds as regards the general 

 morphology of the formed elements of their cytoplasm. 



METHODS. 



The problem of how to study plant cells is one which seems 

 to have received astonishingly little attention. The most ex- 



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