210 proceedings of the academy of [1884. 



July 22. 

 Mr. Thomas Meeeian, Yiee-President, in the chair. 

 Eleven persons present. 



July 29. 

 Mr. Thomas Meehan, Yice-President, in the chair. 

 Eight persons present. 



Sexual Characteristics in Zinnia. — Mr. Thomas Meehan, 

 referi'ino; to some so-called double Zinnias on the table, remarked 

 on the change of sexual character which followed the change of 

 a tubular to a ligulate floret This was not confined to Zinnia, 

 but occurred in Dahlia, and, he believed, all composite flowers. 

 It must be a well-known fact, but had not, so far as he knew, 

 been placed on record. It was well worthy of study by those 

 interested in the laws of sex. In Zinnia a single ligulate floret 

 would often be surrounded by tubular and hermaphrodite ones; 

 but it would have the purely pistillate character of the ray florets. 

 In like manner, when, in the double Dahlia, the tubular florets 

 became ligulate, the neutral character of the ray florets followed 

 with them. It was evident that in these cases there was an 

 intimate connection between the form of the floret and its sexual 

 character. There was even a diff"erence in the form of the akene 

 in the diff'erent florets of Zinnia. The ligulate female floret had 

 a broad akene, tapering at the summit, and with the apex very 

 hairy ; while the akene of the tubular hermaphrodite floret was 

 truncate, and entirely smooth. 



He made some further remarks on the growth of the floret in 

 connection with that of the staminal tube. In many compositae 

 the growth of the pistil continued for a day or two after the 

 corolla had ceased to grow, pushing up often to a length double 

 that of the corolla. In Zinnia the growth of the floret was 

 enormous on the last day, often doubling its previous length in 

 twenty-four hours. It always remained longer than the pistil, 

 until it withered away, when the expanded arms of the pistil were 

 exposed. The anther cells burst before tiie floret opened, and, 

 though the arms could not expand, enough pollen entered by the 

 stigmatic fissure to ensure self-fertilization. 



The following was ordered to be printed : — 



