1904] SHULL—PLACE-CONSTANTS FOR ASTER 359 
siderable change in the constants of variable characters during the 
single season is now generally recognized, as has been made manifest 
inthe discussions which were roused by LUDWIc’s (1901) interpretation 
of such differences as indicative of the establishment of local races 
ot petites especes. Miss LEE (1902) says in her discussion of Lupwic’s 
results and conclusions, ‘‘ we require in fact to know how the means, 
variabilities, and correlations of the characters of a plant change 
(i) with its season and (ii) with the influence of environment before 
we can formulate a test for racial differences,” and PEARSON (1903) — 
and other recent writers make similar statements. 
While there is thus a general recognition of the changes which 
may be expected to take place during a single season, there is still a 
question as to changes of variability from season to season. This 
is the first investigation in which factors involved in modifying the 
variable characters of plants or animals have been so completely 
limited to the dissimilarity of different seasons. Although a number 
of students have at times found differences similar to those presented 
in this paper, their‘material has been collected nearly always in such 
@ Way as to allow of some other interpretation, and the conclusions 
ammived at have in consequence usually assumed the absence of 
Seasonal fluctuations. | 
YULE (1902) has investigated the number of sepals of Anemone 
nemorosa growing in several different habitats in the neighborhood 
of Bookham, Surrey, England, during the years 1889-1900, but 
unfortunately his collections were not made at coincident dates of 
~ Several years, and one of the habitats had changed during the 
aa Which the observations were made from an exposed clearing 
ie ell-grown shady copse. Although he interprets his results as 
ecg 4 considerable fluctuation from season to season, his data 
thrown into a single series and shown to exhibit just the 
— sy Tecent investigations of REINOHL (1903) an Alsine 
. a the results recorded here for Aster prenanthoides show 
sur during a singl Thus, taking Yuue’s data for 
habit gle season. ; g 
ltat (C), which he describes as a narrow strip of copse at Little 
Which . arranging them according to the time of year at 
& % collection was made, without regard to the year, we have 
€an number of sepals: April 8-12, 1899, 6.63; April 15, 
