502 Morphologie, Teratologie, Befruchtung, Cytologie. 



of the pod for maturing its ovules into seeds, the pods with the 

 larger number of ovules producing relatively fewer seeds. 



In a subsequent paper, these conclusions will be tested upon 

 the more homogeneous collections of pods from individual trees. 



Jongmans. 



Harris, J. A., Further observations on the relationship 

 between the number of ovules formed and the number 

 of seeds developing in Cercis. (Bull. Torrey Botan. Club. 

 XLI. p. 533—549. 4 Fig. 1914.) 



The investigations establish several points concerning fertility 

 and fecundity. 



a. The physical constants — tj^pe, variability, and correlation — 

 of the number of ovules per pod and the number of seeds developing 

 per pod in Cercis canadensis differ sensibly from individual to 

 individual and from Jiabitat to habitat. The data do not. however, 

 justify the conclusion that the trees from the diiferent habitats are 

 to be distinguished taxonomically. 



b. The correlations for number of ovules formed and number 

 of seeds developing per pod have always been found positive and 

 of a moderate, considerable or even high intensity. 



c. Regression is sensibly linear. Possibly, however, there is a 

 departure from linearity in the pods with eight ovules. 



The significance of the linearity of regression is two-fold. 

 Statistically, it justifi.es describing the interdependencc between the 

 number of ovules formed and the number of seeds maturing by the 

 coefficient of correlation. Biologically. it shows that the^rate of 

 increase in number of seeds developing per pod remains the same 

 as we pass from pods with the lowest to pods with the highest 

 numbers of ovules. 



d. Wherever large series of pods have been examined, the 

 correlation between the number of ovules per pod and the capacity 

 of the pods for maturing their seeds has a negative sign and a low, 

 usually a very low, magnitude. When the number of pods is relatively 

 small the coefficient is sometimes positive. These results may well 

 be due to the probable errors of random sampling which, with 

 samples of this small size, may be quite large enough to screen 

 such a slight relationship. 



In such cases the number of negative values is generally larger 

 than the number of positive coefificients, and their mean numerical 

 magnitude is always higher. For every large series examined the 

 value of roz has been over 2.5 times its probable error and sometimes 

 many times its probable error. These evidences can leave little 

 doubt of the existence of a slight negative relationship between the 

 number of ovules formed and the capacity ot the pod for maturing 

 its ovules into seeds, the pods with the larger number of ovules 

 producing relatively fewer seeds. 



This conclusion has also been reached in an earlier paper for 

 the dwarf varieties of Phaseohis vulgaris as a whole. 



e. The foregoing conclusions and other Statements made in 

 this paper apply exclusively to the one species considered and 

 should not be extended to others except on the basis of actual data. 

 There is no reason to assume that species may not differ in this 

 regard. The data available for Rohinia, indicate that quite different 

 conditions from those found in Cercis may prevail. If the correlations 

 found for Sanguinavia are based on sufificiently large and represen- 



