30 The Ohio Naturalist. [Vol. IV, No. 2, 



as he is by transmissionists, both as men of science on the one 

 hand and with fanciers on the other, one would expect him to 

 follow. But he does not, and as a conclusion to these remarks 

 and as an expression of what the speaker deems the sentiment of 

 those biologists who have worked more especially in this field, 

 the following summary of his experiments, given by himself before 

 the British Association, is appended : "In my experiments I 

 have never seen anything that would point to the transmission of 

 an acquired character." 



Note. — Since the above was prepared, a volume from Macmil- 

 lan & Co. , written by Thomas Hunt Morgan and entitled ' ' Evo- 

 lution and Adaptation" has appeared. In this book is found a 

 treatment of the general subject in the light of recent research. 

 It may be said that the transmission hypothesis is not counte- 

 nanced by this author. 



NOTES ON THE NUTATION OF PLANTS. 



John H. Schaffner. 



In the summer of 1896, the writer studied the nutation of Hel- 

 ianthus annuus ( i ) and found that in this plant we have one of 

 the most remarkable and striking diurnal phenomena to be ob- 

 served in the plant kingdom. It has been believ^ed quite generallj^ 

 that the disc of flowers follows the sun but Kellerman (2 ) showed 

 conclusively that this is not the case. The nutation occurs in the 

 upper part of the stem before anthesis, the terminal rosette fol- 

 lowing the sun from morning until sunset. Along with H. annu- 

 us, H. scaberrimus was studied and found to act in the same 

 way. 



In 1900, the cultivated variety of H. annuus was reported (3) 

 to nutate as strongly as the wild variety, and the same was 

 observed in regard to H. petiolaris. 



More recently Stevens (4) has shown that a similar nutation 

 occurs in various other genera of widely separated families. He 

 found nutation in Bidens frondosa and Ambrosia artemisaefolia. 

 He also mentions the genera, Amaranthus, Lespedeza, Melilotus 

 (especially M. alba), Medicago, and Trifolium, as containing 

 species which show more or less nutation. 



During the past summer numerous observations were made on 

 various plants in Clay county, Kansas. 



The writer had himself noticed the nutation of Ambrosia trifida 

 in 1897, but it was not included in a previous report as no careful 

 observations had been made. The giant ragweed nutates very 

 decidedly when conditions are favorable, often bending 90° to the 

 west in the evening. In the morning the bending of the stem is 



