THE 



Ohio Journal of Science 



PUBMSHED BY THE 



Ohio Statk Univkksity Scientific Society 



Volume XVIII FEBRUARY, 1918 No. 4 



TABLE OF CONTENTS 



SCHAFFNiCR — The Expression of Sexual Dimorphism in Heterosporous 



Sporophytes 101 



Walton— Eutetramorus Glohosus, a New Genus and Species of Alg^e 



Belonging to the Protococcoidea (Family Crelhstiidte i 126 



Pott — A Study of Cattle "Temperament" and its Measurement 129 



THE EXPRESSION OF SEXUAL DIMORPHISM IN 

 HETEROSPOROUS SPOROPHYTES.* 



John H. Schaffner. 



The writer has been engaged for a number of years in 

 studying the evolutionary development of the higher plants. 

 In the study of the flower, the problems of sexuality and of 

 sporophyte dimorphism have presented themselves in an 

 unusual manner, w4th many hints as to the nature of their 

 hereditar}^ expression. 



The most remarkable dimorphism in plants is, of course, the 

 difference of form and function expressed between gametophyte 

 and sporophyte. One can hardly conceive of a more funda- 

 mental difference than exists, for instance, between the two 

 generations of the ordinary ferns. In the higher plants this 

 dimorphism is as extensive as sexuality itself. Sexual di- 

 morphism seems more prominent to us only because we con- 

 stantly associate our ideas with the sexual dimorphism of the 

 higher animals. 



Aside from the dimorphisms mentioned above there are also 

 very striking vegetative dimorphisms which have no relation 

 to sexuality or the alternation of generations. Such vegetative 

 dimorphisms are usually expressed in different parts of the same 

 individual. In plants like Megalodonta beckii (Torr.) Greene 

 and Neobeckia aquatica (Eat.) Britt., the dimorphism is 



♦Contribution from the Botanical Laboratory, Ohio State University. No. 99. 



