OBSERVATIONS ON THE NUTATION OF HELIAN- 
THUS ANNUUS." 
JOHN H. SCHAFFNER. 
In the year 1890 Kellerman? reported some observations on 
the nutation of the sunflower, in which he concluded that, con- 
trary to an almost universal popular belief, the heads of 
Helianthus annuus do not turn with the sun, facing toward the 
‘a in the morning and gradually moving westward until even- 
mg. He considered the belief mainly traditional, although he 
found some movement through a very small space, but rarely if 
‘Yer through a space approaching a half circle. He suggested, 
However, that nutation might be more marked in the head pre- 
“lous to anthesis. 
Having been a firm believer in the supposed nutation, and 
"calling numerous instances which seemed to support the 
delief, the writer desired to ascertain for himself the true facts 
Mthe case and also the conditions which may have given rise 
"S the traditional belief. Accordingly a long series of observa- 
: tions were made in Clay county, Kansas, during the summers of 
896 and 1897, extending in both years from June to Septem- 
ie os The summer of 1896 was especially favorable for the 
pidy » there being a more abundant and luxuriant crop of this 
thatacteristic western weed than usual. The western variety of 
Me lanthus annuus differs considerably in many anatomical 
‘haracters from the common cultivated variety which was not 
‘iteluded : i 
“Mcluded in the study. The observations of the second seaso 
a entirely a confirmation of those recorded during ie oer 
— *Contributi 
, j me a 
oy ons from the Botanical Laboratory, Ohio State meee 14: 190- 
18 vanetvations Oa the nutation of sunflowers. Trans. Kae. Ave =r 
Too 90, 
18) 
395 
