356 BOTANICAL GAZETTE [NOVEMBER 
TABLE H. 
COEFFICIENTS OF CORRELATION. ~ 
1900 1903 
Mayeand bracts. i<.......... -7O5t+ .0002 5. .8745+ .0042 
Rays and disk-florets........ .6749 + .o100 .8240+ .0058 
Bracts and disk-florets...... ee eee .8355 + .0055 
V. DISCUSSION. 
In my earlier study the conclusion was reached that the mean 
number of parts in the heads of Aster prenanthoides begins high 
and falls continuously from the beginning to the end of the flowering 
season. This was recognized as in accord with BurKIL1’s (1895) 
results on Alsine media and other species. REINOHL (1903) has 
recently made a very careful study of Alsine media and reports that 
the first flowers never have the highest number of stamens and that 
the maximum number is reached only after some time. He attributes 
BURKILL’s results to the fact that they were based upon occasional 
collections which, he supposes, did not happen to involve the very 
earliest flowers of the season. My collections of Aster prenanthoides 
in 1900 included all the heads which bloomed that year, but the first 
collection was made so late that.the mean numbers of parts in the 
very earliest heads were indeterminable because of their association 
with heads of later development; but in 1903 the collections were 
made with such frequency as more closely to analyze the changes 
taking place during the season, there being presented here twelve 
successive collections instead of four. 
It is now shown that in Aster prenanthoides also the mean numbers 
-begin low, leaping almost immediately to the maximum, and megs 
falling more gradually till near the end of the season. Inspection 2 
jig. 7 will make it clear that four collections in 1903; made wos 
same dates as the 1900 collections, would have led to the pram 
then reached that there is a continuous fall from the beginning a 
end of the season. 
It will be noted in the same figure that the las ; 
Shows a rise in mean values. As this collection consist 
heads, it can be considered as having little significance. 
however, that this condition will be found to occur not infreq 
t collection in 1993 
ed of but four 
I believe; 
uently. 
