CONTEIBUTION TO A STATISTICAL STUDY 
OF THE CEUCIFER^. _ 
VARIATION IN THE FLOWERS OF LEPIDIUM DRABA LINN^US. 
By JAMES J. SIMPSON, M.A, D.Sc. 
CONTENTS. 
Page 
I. Introductory . . . . . . . . . .215 
II. Botanical 217 
1. Specific Characters. . . . . . . . .217 
2. Mori)hology of the Flower 218 
3. Conception of Chorisis 219 
4. Orientation of tlio Flower 220 
III. Examination of the Data 222 
1. Classification .......... 222 
2. Analysis 223 
IV. Statistical 242 
1. Study of the Means and Standard Deviations . . . 242 
2. Study of the Correlation Coefficients 245 
V. Morphological Significance of the Statistical Results . . . 251 
VI. Variation in the Gynsecium ........ 255 
VII. Suggestions for Future Studies in this Plant 257 
I. Introductory*. 
In the summer of 1905 Professor J. W. H. Trail drew my attention to an 
extraordinary example of variation which occurred in the several organs of the 
flowers of Lepidium Draha Linnteus. At that time I examined in detail 1832 
individual flowers taken from a single plant growing in a piece of uncultivated 
* I am pleased to have this opportunity of expressing my great indebtedness to Dr J. F. Tocher for 
invaluable assistance in the biometric part of this paper. The correlation and other constants were 
calculated in his laboratory, and without his assistance the publication of this paper would have been 
greatly delayed. I must also thank Professor Karl Pearson, in whose department in University College, 
London, the statistical study was originally undertaken, for reviewing this paper for publication and also 
for much kindly criticism and advice. To Professor Trail my thanks are also due for many botanical 
hints. 
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