148 HARSHBERGER— STUDY OF THE CLOVERS. 



depression the following day, June 5, and a sharp rise to the night 

 position at 6 P.M. 



The morning of June 6 showed a gradual downward movement 

 of the curve until 9 A.M. 



Plant jp-, Trifolium hybridum. — A mature plant in flower gave a 

 curve with a sharp valley and peaks. Starting at 12 M., June 10, it 

 shows a sharp angular drop to 3 P.M., then a sharp rise and as sharp 

 a depression during the late afternoon. After nightfall there was a 

 precipitous rise during the night, then a sharp drop and a rise until 

 about 10 A.M. on June 11. The curve then took a drop to noon, 

 when it began to rain, and a sharp rise to the late afternoon, when it 

 probably cleared. At 6 P.M. it made a steep up curvature during 

 the period of night. 



Plant 40, Trifolium agrarium (an old plant). — A lateral leaflet 

 was tried, so that its curve does not correspond in general with the 

 curves taken for the terminal leaflets. Starting at 11 A.M., June 12, 

 we find the elevation of the curve is followed by a steep depression 

 until 6 P.M., when the curve remains nearly horizontal until the next 

 morning, when it rises rapidly to 9 A.M., followed by a depression 

 until 3 P.M., when there is a rise to 6 P.M., and then a gradual fall. 



Plant 42, Trifolium incarnatum (Plate V). — The curve of the 

 crimson clover is fairly constant with an almost level depression dur- 

 ing the day of June 10, a rounded elevation during the night, a de- 

 pression with a sharp hump in the early morning of June 11 before 

 9 A.M., followed by a depression and a small rise after 12 M., when 

 it began to rain. At 6 P.M. the upward movement of the curve for 

 the night period is observable. 



Plant 4j, Trifolium repens. — An old mature plant in flower was 

 studied as to the movements of the terminal and lateral leaflets. The 

 curve for the terminal leaflet rose from 11 A.M., June 12, during the 

 afternoon with a sudden downward movement to 6 P.M. The night 

 period was characterized by a steep upward curvature followed by a 

 drop during the small hours of the night, and a sharp rise before 

 9 A.M. on June 13. It is such a sharp rise which leads one to 

 suspect that moisture may be a controlling factor. A rise of the 

 curve to 3 P.M. is observable, and then a gradual downward curva- 



