242 Contribution to a Statistical Stud?/ of the Crifci/erce 
IV. Statistical. 
The analysis which we have given of 1813 flowers is sufficient to show that the 
idea of a definite fixed number of sepals in the calyx, of petals in the corolla, of 
stamens in the audroscium or of carpels in the gynascium of cruciferous plants is 
not upheld by an examination of a large number of flowers of this species. In 
less than 1 per cent, of the flowers examined thei'e was an increase* or decrease 
in the number of sepals in the calyx ; in less than 1 per cent, there was also an 
increase or decrease in the number of petals in the corolla, but in 2 per cent, there 
was an increase in the number of stamens in the androecium, while in 22 per cent, 
there was a decrease in the number. 
Since then the number of sepals, petals and stamens is not absolutely fixed for 
any of the organs it becomes necessary now to consider whether the number of 
members in one organ is related to tlie number in the others. 
As has already been pointed out we have not only to consider organs as a 
whole, but, in the case of the calyx and the androecium, the constituents of these 
organs, owing to the fact that these organs are each divided into two separate 
whorls which are inserted at different levels and are placed in directions at right 
angles to one another. 
Further, a special study has been made of the various positions in androecium 
to ascertain to what extent bilateral symmetry may be regarded as an inherent 
character of the flower under consideration. 
By this means also it seems that some definite information might be obtained 
with regard to the perplexing and, at present, hypothetical theory of chorisis, the 
reasons for the existence of which have been summarised on p. 219. 
The statistical part has been divided into two sections: 
(1) a study of the Means and Standard Deviations, and 
(2) a study of the Correlation Coeflicients. 
1. Study of the Means and Standard Deviations. 
Although it is obvious from the analysis of the data under consideration that 
the numbers given for the botanical floral formula, namely, Calyx — 4, Cox'olla — 4, 
Stamens — 6 and Gynascium — 2, ate the nearest integers, it is not at all certain 
from a mere inspection of the tables whether the actual means deviate ft'om this 
number in the direction of excess or deficiency. 
* Where chorisis of a sepal or petal has resulted in two or more distinct individuals we have regarded 
each of these as a distinct sepal or petal in recording the numbers. This method is natural however 
inasmuch as it is the only means by which we may possibly trace reduplication of parts. 
