University Studies 



Vol. VII OCTOBER, njoj No. 4 



I, — A Synopsis of Plant Phyla 



BY CHARLES E. RESSEY 



This paper embodies an attempt to arrange the natural groups 

 of plants in accordance with a theory of the evolution of the 

 V^egetable Kingdom. It is here assumed that that theory includes 

 the following dicta : 



1. In general the lower plants came into existence first. 



2. In general the higher plants sprang from the lower. 



3. Higher plants are more complex than the lower. 



4. Structures with many similar parts (homogeneous) are lower, 



those with fewer and dissimilar parts (heterogeneous) are 

 higher. 



5. Evolution is not always upward, but often it involves degrada- 



tion and degeneration, 



6. Evolution does not necessarily involve all organs of the plant 



equally in any particular period. 



7. One organ of a plant may be advancing while another is 



retrograding. 



8. Upward development is sometimes through an increase in 



complexity, and sometimes by a simplification of an organ 

 or a set of organs. 



9. In some cases particular structures become more simple, while 



the plants themselves become more complex. 



Univkrsity Studies, Vol. VII, No. 4, October 1907. 



