240 IOWA ACADEMY OF SLIEXC'E Vol. XXV. 1&18 



sperm unless the manner of its fruetifie.ition ea)i l)e established 

 in eonsiderable detail. The Pteropsida therefore represents a 

 hiiildy unified, natural series. The series is divided wholly on 

 the question of seeds. Sinee. then, there is at present no term to 

 designate the fern section of this great phylum. I have proposed 

 for this lower seedless group the name Aspermge, suggested by 

 my colleague Miss M. L. Sawyer. The term corresponds ai^tly 

 with the accepted names of the two higher groups, Gymno- 

 spermas and Angiosperma^. 



Up to the last step this classifieation has the advantage of 

 dichotomy. This is an assurance of simplicit.w It follows 

 strictly those great biological characters which have intiueneed 

 the trend of evolution, and which have themselves appeared in 

 response to world-phenomena of cosmic origin. Its general ac- 

 ceptance would certainly help the student to tabulate our 

 present thought regarding plants, and to think correctly in 

 pursuit of further knowledge. 



Department of I'otaxv, 

 Grinxell College. 



