ABNORMALITIES IN INFLORESCENCE OF SPIRAEA VANHOUTTEI 627 
Confining our attention to records from plants in which 
abnormality occurs in considerable abundance, we may ex- 
amine the actual and the percentage frequencies given in 
Table I. Here the frequencies for 1909 represent the results 
of countings on 18 individual plants. Those for 1913 are 
based upon determinations on three large individuals grow- 
ing at Cold Spring Harbor. 
The figures show clearly that the number of inflorescence 
with no abnormal rays is far in excess of these with any 
other number. Thus in 1909 61.5 percent and in 1913 from 
34 percent to 40 percent of the inflorescences were without 
abnormality, and this notwithstanding the fact that all 
these series of material were selected for abnormality. 
Furthermore the frequency of the inflorescences decreases 
as the number of rays which are abnormal increases. This 
is evident from Table I, the results of which are represented 
graphically in diagram I. 
In the foregoing table and diagram the percentage fre- 
quencies have been computed by using the total number of 
inflorescences as a base. It is instructive to determine the 
relative frequen- 
cies of different 
number of ab- 
normalities in 
the inflores- 
cences which 
have at least one 
abnormal pedi- 
cel. The results 
are shown in 
Table II, and represented graphically in diagram 2. 
Both methods give skew distribution, the highest frequency falling 
on o or I abnormal ray, and the frequency decreasing from this class 
to those with higher numbers of abnormal pedicels. 
That the skewness of distribution of the number of abnormal 
pedicels per inflorescence is not due to skewness in the distribution 
of number of pedicels in the inflorescence as a whole is shown clearly 
by diagram 4, which gives the percentage frequencies of number of 
pedicels in three of the series. All of these distributions are fairly 
symmetrical. 
/so 9 iSPhnts 
J9/3. V/antI 
ASnor/rta/ T^edice/s 
Diagram i. Percentage frequencies of number of abnormal 
pedicels per inflorescence in all inflorescences. 
