368 THE AMERICAN NATURALIST. [VOL. XXXVIII. 



botanist cannot be expected to master. Those who work in this 

 field are considered as in a department by themselves and are 

 labeled cytologists which is sometimes given as an excuse for 

 knowing little about their results. Cell studies are nothing more 

 than morphological and physiological investigations which are 

 frequently so broad as to break the mould of the narrower mor- 

 phology and physiology of former years. Cell studies must be 

 the foundation of all exhaustive work in morphology and physi- 

 ology. Indeed among the lower plants they constitute almost all 

 there is to morphology and will determine the classification and 

 relationships of great groups. There are no better illustrations 

 of this fact than the effect of Prof. Harper's investigations on 

 the ascus and sporangium upon Bref eld's theory of the origin of 

 the Ascomycetes. And again the results of several investigators 

 upon the multinucleate gametes found among the Phycomycetes 

 and Ascomycetes are of the utmost importance to a correct 

 understanding of the phylogeny of these groups. When students 

 of the plant cell refuse to accept the stamp of cytologist and 

 insist and show that their work is simply fundamental mor- 

 phology and physiology we shall break away from a past that 

 should be outgrown. 



The material of these papers will be treated under the follow- 

 ing heads. 



TABLE OF CONTENTS. 



Introduction. 



SECTION I. STRUCTURE OF THE PLANT CELL. 

 i. Protoplasmic Contents. ' 



(a) The Nucleus. 



(b) The Plastids. 



(c) Cytoplasm. 



1. Plasma Membranes. 



2. Trophoplasm. 



Coenocentra, Nematoplasts, Physodes. 



3. Kinoplasm. 



Centrospheres, Centrosomes, Asters, Filarplasm, Ble- 

 pharoplasts. 



