2 Harris, Observations on the Physiology of Seed Development in Sta^j/zylea. 



Garden. In auother place, the relationship between the characters 

 of the inflorescence aucl the nuniber of ovules has been discussed.i) 



In both of these papers the problems of fertility and fecundity 

 were quite subsidiary, but the results were hardly what I had 

 expected, and it seems desirable to present here the results of a 

 study of three large series of data with special reference to the 

 problem of the factors influenciug' the development of the seed. 



The tables of data and the constants included here are almost 

 without exception published for the first time, but the three series 

 of material — all from the North American Tract of the Missouri 

 Botanical Garden — have been utilized for other relatiouships in 

 the two papers cited above. Hence it is unnecessary to discuss 

 material or methods^) in detail. 



IL Number of pods per inflorescence and fertility 

 and fecundity. 



Given a species in which the inflorescence produces fruits 

 from only a small proportion of the flowers which it bears, and in 

 which the fruits, in their turn, mature only a small percentage 

 of their ovules into seeds, it seems of considerable physiological 

 interest to ascertain whether the inflorescences bearing- a large 

 number of fruits are more (or less) able to mature their ovules 

 into seeds than those having a smaller number. Has the competion 

 of several fruits for the plastic material available for a particuliar 

 inflorescence the effect of lessening the chances of the ovules of 

 a fruit developing' into seeds? Or, on the other hand, are the in- 

 florescences with more than the average number of pods so much 

 more vigorous that their fruits also mature a larger number of 

 seeds? 



We have an interesting sug'gestion along' this line in the work 

 of Waldron 3) on oats. He found that the correlation between 

 the number of grains per head and the mean weight of the grains 

 was strongly negative, i. e. the heaviest grains were produced by 

 the smallest heads. In the case of Celastrus, however, there is no 

 trustworthy indication *) of an interdependence between the number 

 of flowers formed per inflorescence and the number of seeds maturing 

 per fruit, or between the number of fruits matured per inflorescence 



^) Harris, J. Arthur, Further Observations on the Selective Elimination 

 of Ovaries in Staphylea. (Zeitschr. f. ind. Abst. u. Vererbungsl. In press.) 



^) The familar biometric methods have been employed in the analysis of 

 the data. The means and Standard devinations are omitted, since they have 

 no direct bearing on the problems discussed. Sheppard's correction was not 

 used. 



^) Waldron, L. R., A Suggestion on Ooncerning Heavy and Light 

 Seed Grain. (Ann. Nat. Vol. XLIV. 1910. p. 48-56.) 



*) Harris, J. Arthur, Correlation in the Inflorescence of Celastrus 

 scondens. (Ann. Report. Mo. Bot. Card. Vol. XX. 1909. p. 116-125.) 



