—e 
aS eo ee 
1894] 
Leaf Movement in Cercis. 219 
in each case is marked with a negative sign. The tempera- 
ture at the time the observation was made is given in a col- 
umn near the right. 
These observations were made about the first of March on 
small plants grown in the green house that were brought 
from the forest in the previous autumn. The average move- 
ment given in the last column in each table together with the 
temperatures are shown above plotted in the form of curves. 
Curves a, 6, and c correspond respectively with tables 1, 2, and 
3. Curves dand ¢ are temperature curves; d corresponding 
with table 1, and e¢ with tables 2 and 3 (the observations in 
o'clock A. M. is taken as a starting point in each case, thereby 
admitting of the graphical representation of the actual posi- 
ton of the leaves at any given time as well as of their ave- 
fave Movement. The degrees of the angles are represented 
on the ordinates, and the time in hours on the abscissa. 
The noon point is marked 12 mM. _ Fractions of a degree less 
tenths and over they are counted as one. The degrees of 
temperature for Curves d@ and e are indicated at the right 
aR the top. In comparing curves a and 4 it will be seen 
a ue the forenoon maximum is reached much later, and 
Gavi ¢ fall of the leaf in the afternoon takes place much 
amerthanin a. This may be attributed to the fact that in 
<S edienage day in the case of a. Curve c is to represent 
give wits of the observations made on the basal pulvinus, as 
Be teele3. The curve seems to indicate a slight 
the petiole during the middle of the day, but on 
the difficulty experienced in reading the leaf 
iSasa actions of a degree, I do not feel safe in giving 
Photogra = conclusion, Fig. 1 and 2, plate XIX, are from 
at nigh Pas and show respectively the position of the leaves 
ion in tents’ O'Clock a. M.), as compared with their posi- 
FE vaytime (eight o'clock A. M). 
trelve cn istological investigation of this subject a series 
ing of th “ctlons were made, beginning with the first swell- 
® leaf buds in spring and ending with the mature 
