186 



NATURAL SCIENCE 



[March 



combined average of 12 parts, but instead of each having 6, as we 

 should assume from the formula being normally 5 and 5, the calyx 

 remains the same, 5, and the corolla rises to 7. In further analysis 

 of the last statement, the mean of the 262 specimens in which 

 the calyx had 5 sepals and the corolla more than 5 petals, is — 

 petals, 6*9; stamens, 52'4; carpels, 37*4. The extra material 

 available has increased the corolla by 1'9 members (or more strictly 

 by 1'4), and has also added to the carpels; but in these specimens 

 the stamens are decidedly below the general mean. 



We may assume therefore, from the foregoing, that if there is 

 any plus variation in any specimen, the chances are that the calyx 

 will remain normal, the corolla and carpels be increased, while the 

 stamens will be below the mean. 



FIG. 4. — VARIATION IX CARPELS OF 500 SPECIMENS OF RANUNCULUS REPENS (L.) 



First Series. 



■<- 



-NUMBER OF CARPELS- 



(The formula given by the 8 specimens with corolla below the- 

 mean is — calyx, 5 ; corolla, 4 ; stamens, 55'3 ; carpels, 40 '5.) 



Correlation of Variation in Stamens and Carpels 



Number of specimens having 

 stamens 54 and carpels 



Less than 



54 

 54 

 54 

 54 

 54 

 More than 54 

 54 

 54 



