(170 ) 
An examination of the above tables and figures brings out 
the following points: If we take in each group the leaflet 
which has the greatest positive change of position, z. ¢., the 
greatest change from a more basal toa more terminal location, 
and the leaflet which has the greatest opposite change, we get 
a very striking result. /n each case where there ts a con- 
stderable rotation from a more basal to a more terminal post- 
tzon we get a relative increase in length and where there ts 
an opposite rotation we get a relative decrease in length. 
Using the ‘‘ 4A” length-changes as our basis of comparison 
we get in the ‘“ AB” group a change in length of + 1.0 mm. 
for the greatest plus change of position and of — 1.0 mm. for 
the greatest minus change. Likewise in the ‘* BC” group 
we get a change of + 1.5 mm. for the greatest plus change 
of position and of — 2.6 mm. for the greatest minus change. 
In the ‘“C#” group in a similar way we have a length- 
change of + 2.2 mm. for the greatest plus position change 
and of — 1.3 mm. for the greatest minus position change. 
It will be noticed that some of the leaflets with a compara- 
tively small change of position show a variation in the rela- 
tion to length, but this is certainly to be expected from the 
nature of the experiments. 
The small number of cases in each group and the conse- 
quent large probable error of the averages is more than 
counteracted by the great uniformity of results, and it would 
certainly be surprising if the latter did not indicate a true 
correlation. 
GENERAL REMARKS. 
The facts brought out by the foregoing experiments seem 
to indicate that we have here a very fruitful and as yet prac- 
tically untouched field for the study of the correlations of 
plant members. The interesting regulations of position and 
length which we have found in the leaflets of the compound 
leaf indicate the need of an extension of the method to leaves 
in other morphological relations as well as to different organs 
of the plant body. While correlations of size have been 
